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Red ceramics enhancement by hazardous laundry water cleaning sludge
Journal of Cleaner Production xxx (2016) 1e7
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Red ceramics enhancement by hazardous laundry water cleaning sludge Nagalli 1, Rodrigo E. Catai 1, Ronaldo L.S. Izzo 1, Vsevolod Mymrin*, Kirill Alekseev 1, Andre Juliana L. Rose 1, Haroldo A. Ponte 1, Cesar A. Romano 1 , Str. Deputado Heitor de Alencar Furtado, 4900, Campus Curitiba, CEP: 81280Civil Engineering Department of Federal Technological University of Parana , Brazil 340, Ecoville, Parana
a r t i c l e i n f o
a b s t r a c t
Article history: Received 25 July 2015 Received in revised form 17 December 2015 Accepted 19 December 2015 Available online xxx
Permanently increasing number of industrial and municipal wastes accumulated in the dumps, inevitably leads to contamination of soils, surface waters and subterranean waters, the atmosphere and is a perceptible factor of climate change on our planet. This paper is one more proof that waste utilization, as a valuable source of components for new materials production, is environmentally and economically the best way for their management. The purposes of the research were the next: to develop eco-friendly ceramics that include and immobilize hazardous laundry sludge after cleaning of extremely polluted industrial uniforms with high contents of As, Ba, Cd, Pb, Cr, Hg, Cu, Zn and grease, oil, resin, tar, paints, organic volatile compounds, etc.; to improve the mechanical properties of red ceramic, using laundry sludge; to demonstrate a possibility of natural raw materials extraction decrease, partially replacing them with laundry sludge. This sludge was introduced in the traditional clay-sand mix in the amount of 0, 3, 5, 7, 10, 15 and 20 wt. %. After sintering of these composites at temperatures 1000 , 1050 , 1100 , 1150 C the maximum values of flexural strength resistance of the ceramics was 15.6 MPa, values of linear shrinkage ranged from 4.5 to 14.1%, water absorption values e from 13.0 to 20.3%, and density values ranged from 1.65 to 1.83 g/cm3. All these characteristics of the mechanical properties of the developed materials significantly exceed the properties of ceramics from traditional clay-sand mixes without laundry sludge. The leaching and solubility values of the heavy metals immobilized within these ceramics are hundreds of times lower than threshold levels set by the national standards of Brazil. This study showed that industrial laundry sludge can be safely used as additive to ceramics in proportions of 10e20% wt. %, enhancing the mechanical properties of the materials and constituting an ecological way to manage these wastes. © 2015 Elsevier Ltd. All rights reserved.
Keywords: Sintering Composites X-ray methods Chemical properties
1. Introduction Some types of industrial and municipal wastes are extremely hazardous because of their high content of dangerous components, such as concentrated heavy metals. One example is laundry sludge (LS) from extremely polluted industrial uniforms, containing many heavy metals including As, Ba, Cd, Pb, Cr, Hg, Cu, and Zn. Their concentration far exceeds Brazilian toxicity thresholds, and therefore, this type of LS must be classified as hazardous waste. The most
* Corresponding author. Tel.: þ55 41 3279 4518. E-mail address: [email protected] (V. Mymrin). 1 Tel.: þ55 41 3279 4518.
common practice is to discharge this waste directly into landfills (Richter, 2004). There is extensive scientific and technical literature on finding environmentally safe and economical methods to use waste as a raw material (Mymrin, 2012; Pan et al., 2001) including sewage sludge from water cleaning. One of the more widespread methods is the use of waste sludge to produce ceramics (Ramirez et al., 2008; Teixeira et al., 2006; Oliveira et al., 2004). Herek et al. (2012) studied the use of different concentrations of textile laundry sludge for ceramic brick production, and Abdul et al. (2004) used sewage sludge as a raw material in red brick firing. Dondi et al. (1997) classified industrial sewage sludge as a valid material flux in ceramics fabrication, and Leite and Pawlowsky (2002) used it to plastify waste. Mahzuz et al. (2009) developed a method to use n arsenic-contaminated sludge to produce ornamental bricks. Jorda
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(2005) reported that sewage sludge can decrease the bending strength of construction materials. However, other study (Ramirez et al., 2008) showed a positive influence of the sludge on the mechanical properties of concrete and mortar. Pietrobon et al. (2004) came to a neutral conclusion: they reported that the addition of 10%, 20% and 30% of sewage sludge negatively altered the structure of cement, but that the difference was not critical. Additionally, Castro (2010) examined the acoustic properties of ceramic blocks. John et al. (2001) successfully used WTPS as an additive to cement mortars. Kizinievi c et al. (2013) analyzed the influence of WTPS (from 5 to 40 wt. %) on the physical and mechanical properties, structural parameters as well as mineralogical composition of the ceramics sintered at 1000 C and 1050 C. Anyakora (2013) used WTPS by adding 90% of natural clay to produce the brick. Alqam et al. (2011) investigated the use of WTPS (10e50 wt. %) used cement in the production of paving tiles. The researchers of Federal Technological University (UTFPR), Brazil, in the area of civil engineering have fairly extensive experience in developing of new construction materials with extensive use of more than 80 types (Mymrin, 2012) of industrial and municipal wastes as valuable components, which are significantly improving mechanical and chemical properties of these materials. A significant fraction of these wastes are sludge, including the particularly dangerous waste of galvanic sludge. The objectives of this study were as follows: to investigate experimentally the efficiency of using LS from extremely polluted industrial uniforms and possessing a high content of multiple heavy metals, oily wastes and other organic substances; to study the physicochemical process of forming red ceramic structures after composite sintering; and to develop new and environmentally friendly composites for ceramics production, with mechanical properties meeting or exceeding the criteria established by Brazilian technical standards, by using the wastewater sewage sludge from an industrial laundry. As one of the green chemistry principles expresses, wherever practicable, synthetic methods should be designed to use and generate substances that possess little or no toxicity to human health and the environment (Anastas and Green, 1998). In this study, the aim was to include a toxic laundry waste in ceramics production, converting it in a useful material that in this new form does not pose any significant toxicity.
(Brazil). Mechanical resistance was tested using the three-point flexural resistance strength method on an EMIC universal testing machine. The water absorption coefficient by immersion was determined with an Instrutherm BD 200 under the Brazilian NBR 13818/1997 standard. Linear shrinkage of the TS was determined using a digital caliper (DIGIMESS). 2.2. Calculations The flexural rupture strength of the tested specimens (TSs) was measured following standard NBR 15270-3/05 (2005) and using the following equation:
RF ¼ ð3PLÞ= bh2
(1)
where RF is the flexural rupture strength (MPa), P is the maximum load supported by the specimen (kgf), L is the distance between the supports (mm), b is the width of the TS (mm), and h is the height of the TS (mm). Water absorption (WA) was measured according to the Brazilian standard NBR 15270-3/05, (2005), which uses the following equation:
WA ¼ ½ðMSAT MD Þ=MD 100
(2)
where MSAT is the mass of the water-saturated specimen after 24 h of water immersion, and MD is the mass of the dry specimen after sintering. Apparent specific density DA was calculated using the equation
DA ¼ Md=ðMd MwÞ
(3)
where DA e apparent specific density (g/cm3); Md e the weight of the ceramics body in air (g); Mw e mass of the ceramics body immersed in water (g) equal to the volume of immersed specimen (cm3). In accordance with Archimedes' law the weight of a body immersed in the liquid is reduced by the buoyant force acting on the body fluid side; it is equal to the weight of the displaced volume (cm3) of body fluid. 3. Results and discussion
2. Research methods
3.1. Raw materials under study
2.1. Methods
A sample of LS was obtained from the filters of washing machines of the industrial laundry in Curitiba, Brazil, that specializes in cleaning extremely polluted industrial uniforms. Its high calorific value (almost 5300 kcal/kg), density and black color similar to bitumen indicated that these clothes were worn by workers engaged in petroleum extraction and refining. The LS ash content was 28.2%, and the extracted ash mainly consisted (Table 1) of SiO2 (71.5%), Al2O3 (12.74%) and Fe2O3 (8.34%). A very high C.L. (71.8%) was most likely caused by grease, oil and general emulsified oily components, resin, tar, paints, organic volatile compounds, carbonates, and water. A very high content of oily materials precluded
The raw materials and ceramics were characterized using various methods. To determine the chemical composition, a Philips/ Panalytical X-Ray Fluorescence Spectrometer model PW2400 was used. Studies of mineralogical composition using the powder method were performed with a Philips X-Ray Diffractometer, model PW1830, with a monochromatic wavelength lCu-Ka, at 2q range of 2e70 . Morphological structures were determined by scanning electron microscopy (SEM) using an FEI Quanta 200 LV. Chemical microanalyses were determined using energy dispersive spectroscopy (EDS) with an Oxford (Penta FET-125 Precision) X-ACT and by micro-mass analyses using a laser micro-mass analyzer (LAMMA-1000, model X-ACT). The samples of the ceramics with particles diameter <9 mm were washed in deionized water, agitated in solution with pH ¼ 4.8 at 25 C during 18 h and leached extract was separated on a glass fiber filter with a porosity of 0.6e0.8 mm. Leached metals were analyzed using atomic absorption spectrometry method with a Perkin Elmer 4100 spectrometer. Granulometric composition was determined using laser diffraction particle size distribution analysis with a Granulometer CILAS 1064
Table 1 Chemical composition of the raw materials characterized by XRF method. Raw material
LS TM
Concentration, wt.% SiO2
Al2O3
Fe2O3
Na2O
CaO
SO3
MgO
C.L.
71.57 57.50
12.74 19.70
8.34 8.70
1.47 0.10
1.23 0.00
0.87 0.00
1.41 1.40
71.83 7.58
Note: C.L. e calcinations loss.
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investigation of the as-received LS mineral composition by XRD or of its structure by SEM or EDS. The traditional mix (TM) of red clay with sand was obtained from local brick factory in the region of Mariental, in the state of Paran a, Brazil. TM is a common raw material in brick factories worldwide that has similar principal components to LS (Table 1), but with less SiO2 (57.50%) and more Al2O3 (19.70%). Its value of calcinations loss (CL ¼ 7.58%) can be explained by the organic content of the natural clay. A study of leaching and solubility of liquid LS extract (Table 2) by AAS showed that the content of multiple metals far exceeded Brazilian toxicity thresholds NBR 10004 (2004); therefore, the LS can be classified as hazardous waste. The mineralogical composition of TM, as characterized by XRD (Fig. 1), includes illite (K,H3O)Al2(Si3Al)O10(H2O,OH)2 and quartz SiO2 with a relatively high content of amorphous material. Fig. 2 depicts, under high magnification, the particle morphology of the TM raw material as examined by SEM. These micrographs display a wide variation in particle size and configuration with widely varying inter-particle pore shapes. The EDS analysis (Table 3) of the chemical composition of the TM was consistent with the XRF (Table 1) and XRD (Fig. 1) analysis results. The main inorganic components of the TM were amorphous substances with composition that varied considerably at the microscale. Some clay particles exhibited high Si and Al content, which are present in illite, as well as Fe and minor amounts of other elements. Particles with high Ca content may have consisted of carbonate-containing materials; particles with C content may have included carbonates or organic materials such as wood or plant remains. 3.2. Manufacturing of test samples (TSs) The ceramic TSs were manufactured by mixing and homogenizing the raw materials in different proportions (Table 4), moistening to an optimal humidity (10e12%), compacting at 5 MPa in a rectangular form with dimensions 60 20 10 mm, drying at 100 C for 24 h and sintering for 6 h at 1000 C, 1050 C, 1100 C and 1150 C. The TSs of composition 1 were prepared from TM without the inclusion of LS to serve as standard (control) ceramics. 3.3. Mechanical properties of the developed ceramics The average values and standard deviations of the sintered TSs' mechanical properties were calculated based on ten replications (Fig. 3).
Table 2 Results of leaching and solubility tests of the LS and of composition 7 sintered at 1150 C. Elements
As Ba Cd Pb Cr total Hg Se Al Cu Fe Mn Zn
Leaching, mg/L
Solubility, mg/L
LS
Comp. 7
NBR*
LS
Comp. 7
NBR*
9.92 88.28 9.15 6.32 22.15 2.04 2.75 20.13 23.52 39.63 74.18 78.18
0.21 <0.1 <0.005 <0.01 <0.05 <0.001 e <0.10 <0.05 0.07 e <0.10
1.0 70.0 0.5 1.0 5.0 0.1 1.0 * * * * *
12.44 97.15 17.11 8.56 25.72 3.84 3.74 29.28 33.44 53.87 92.74 92.73
<0.001 <0.1 <0.005 <0.01 <0.05 <0.0002 e <0.10 <0.05 <0.05 e <0.10
0.01 0.7 0.005 0.01 0.05 0.001 0.01 0.2 2.0 0.3 0.1 5.0
Note: NBR* e no threshold of the Brazilian standards NBR 10,004 (2004).
3
Fig. 1. Diffractogram pattern of the TM used in this study.
According to the standard NBR 15270-3/05 (2005), solid bricks can be classified by flexion resistance strength as follows: Class A for <2.5 MPa; Class B for 2.5e4.0 MPa; and Class C for >4.0 MPa. When fired at T ¼ 1000 C, the ceramics with LS content ranging from 3% to 20%, exhibited an increase in flexural strength from 2.80 to 5.96 MPa for compositions ranging from 3% to 15% LS, dropping to 5.44 MPa at 20% LS. For T ¼ 1050 C, an increase from 4.79 to 8.69 MPa was observed for compositions ranging from 3% to 10% LS, followed by a steady decrease to 5.71 and 7.50 MPa as LS content increased to 15% and 20%. As a result of sintering temperature increasing to 1100 C the value of TSs of composition 2 with 3% of LS almost stopped, with 5% (composition 3) decreased for 2.01 MPa (from 8.50 to 6.49 MPa), but of compositions 4e7 with 7, 10, 15 and 20% their values of resistance increased by 9.92, 15.42, 15.09 and 15.59 MPa, i.e. in 1.14, 1.79, 2.64 and 2.08 times correspondingly. The next temperature increasing till 1150 C leaded to the growing up of resistance values of ceramics with 3 and 5% of LS contents (composition 2 and 3) by 3.77 and 5.79 MPa (in 1.75 and 1.89 times), but it caused a sharp drop in strength of all following compositions with 7, 10, 15 and 20% of LS contents by 3.21, 1.30, 2.64 and 3.07 MPa respectively. The ribs of the TSs of these compositions were considerably melted and rounded, especially in compositions 6 and 7. Thus, the maximum flexion resistance strength (15.59 MPa) had TSs of the composition 7 after sintering at T ¼ 1100 C, which is 2.68 times higher than the resistance of control composition 1 only from traditional clay-sand mix without LS content. Such complex trends in the flexural strength values of the ceramics as a function of LS content and sintering temperature can be explained by two mechanisms acting in opposition: 1) an increase in LS content increases the combustion quantity of oily components and other organic substances from the formation and expansion of gases that form a network of pores within the sample. These factors lead to a decrease in strength. 2) A high concentration of heavy metals and alkaline detergents acting as fluxes tends to lower the melting point temperature and alloy TM particles and change the microstructure to a durable glass-like material. The data summarized above on LS content versus firing temperature indicate a transition of predominance from the second factor (strength increasing) to the first (strength decreasing). The very large (till 2.66 times) increase in ceramic strength at 1100 C can be attributed to TM melting and a transition to the durable glassy state. However, the flexion resistance strength increased with increasing LS content in all of the developed ceramics listed in Table 4, and all values significantly exceeded the demands of standards NBR 15270-3/05 (2005). Some researchers (Herek et al., 2012; Monteiro et al., 2008) have reported the opposite effect: a reduction in strength with increasing LS content in sintered ceramics. Three reasons could
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Fig. 2. SEM micrographs of TM with EDS points labeled; chemical compositions are presented in Table 4.
Table 4 Compositions of the TSs, wt%. Raw materials
LS TM
Fig. 3. Three-point flexural strength of ceramics sintering at different temperatures.
explain the contradiction between the current study's results with the results of the previous investigations: 1. Previously reported sintering temperatures did not exceed 1000 C, whereas in the present experiments, the sintering temperature reached 1150 C as a melting point of majority of the compositions under study; 2. The amount of metals present in other groups' LS did not exceed thresholds set by the Brazilian standard. In contrast, leaching and solubility tests of the LS used in this research show that some heavy metals are present in concentrations thousands times higher than the maximum permitted (Table 2). For example, the solubility of Cr is 5144 times higher; the corresponding multiplicative factor for a selection of other elements is 3840 for Hg, 3422 for Cd, 1244 for As, and 856 for Pb. This difference in the degree of contamination of LS arises because the above-mentioned authors likely used sludge from municipal laundries that process relatively clean bedclothes, underclothes, and other household laundry. The sample of LS used here was obtained from an industrial laundry that specializes in washing extremely polluted industrial uniforms with a very high content of all types of heavy metals, grease, oil and oily components, resin, tar, paints, organic volatile compounds, and
N of composites/wt.% content 1
2
3
4
5
6
7
0 100
3 97
5 95
7 93
10 90
15 85
20 80
carbonates, among other toxic materials. Each of these three factors could be expected to change the processes of structure formation of developed ceramics, and their combined effect may be the source of such considerable differences between the experimental results. The standard deviation values of flexural resistance of all ceramics increased with increasing sintering temperature, but in no case did they exceed 7% of the average values. The ceramics showed direct dependence between linear shrinkage of the TSs and sintering temperature (Fig. 4). For all sintering temperatures, control composition 1 always exhibited the least shrinkage, except at 1150 when considerable TM melting occurred. Similar amounts of melting were observed in TSs of compositions 6 and 7 with 15% and 20% LS content. The values of shrinkage slowly increased with decreasing LS content and sintering temperature. The addition of even 3% LS to KC (composition 2) at 1000 increased the shrinkage value by 56.9%. The addition of 5% and 7% LS (compositions 3 and 4) increased shrinkage by only 63.5% and 65.2%, respectively. The TSs of composition 5, the most resistant after sintering at 1150 C increased its value of shrinkage 1.18% (from 9.23 till 10.42%) and lost 1.30 MPa in strength; the most resistant after sintering at 1100 C TSs of composition 7 increased at
Table 3 Chemical composition of TM measured by EDS at the points labeled in Fig. 2-C. Point
1 2 3 4 5 6
Chemical composition, wt. % C
Na
Mg
Al
Si
Ca
Ti
Fe
Total
1.43 3.28 15.01 7.39 5.23 1.16
0.93 1.13 0.18 3.14 2.47 3.25
9.34 7.43 0.96 5.15 14.18 9.32
33.53 24.46 15.63 27.23 17.11 22.32
53.28 31.80 53.19 22.14 31.21 28.85
13.29 29.12 5.03 17.00 15.49 20.10
1.16 0.24 0.43 0.67 0.95 11.27
15.27 2.54 9.57 17.28 13.36 3.73
100.0 100.0 100.0 100.0 100.0 100.0
Fig. 4. Dependence of ceramics' linear shrinkage on LS content and sintering temperature.
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1150 C the shrinkage values for 2.13% with a the loss in strength of 3.07 MPa. This fact can be one of the explanations of the TSs of composition 7 resistance decreasing. The values of the WA of the most part of the compositions (Fig. 5) also increased with increasing of LS content, varying from 16.8 to 20.3% at 1000 C and 13.3e15.5% at 1150 C. Generally, WA values decreased with increasing of sintering temperature. Despite the possibility of closed pore formation, which can mask the influence of the porosity magnitude on WA, it is observed from Fig. 5 that WA increased at the temperature 1000 C considerably between compositions 5 and 6. The TSs sintered at 1150 exhibited increasing WA values by 0.4e0.6% between compositions 2e5; between TSs 5e6 and 7 the increase was 2.4 and 2.6%, respectively. In contrast, after sintering at 1150 C the TSs exhibited not increasing, but decreasing WA values for ceramics 2e3, 4 and 5 by the following amounts: 0.7, 0.9 and 1.2%, with increases observed only in ceramics 6 and 7 in the amounts of 1.2 and 0.9%. Similar increases of WA with sludge incorporation were observed by Herek et al. (2012). The failure of compositions 6 and 7 to follow this trend confirms the hypothesis of a sharp increase in the porosity of ceramics with 15 and 20% LS content. This increase is caused by the increasing influence of gases from the combustion of organic substances on the cohesion of TM particles while they are melting. In spite of this, the water absorption of the TSs at all temperatures is less than that of control samples, which exhibited a relatively high amount of water absorption. This finding illustrates one of the significant advantages of these novel materials compared with their conventional counterparts. The materials satisfied standards by this metric as well (NBR 15270-3/05, 2005). Sample density after sintering at different temperatures was calculated in accordance with Eq. (3). In general, the density values of all ceramics smoothly increased (Fig. 6) from 1.65 till 1.83 g/cm3 with increasing of sintering temperature. Compositions 5e7, with the three highest amounts of LS (10, 15 and 20%), exhibited the largest increase of density values (0.05e0.06 g/cm3) between sintering temperatures 1100 and 1150 C, The highest density for all temperatures was measured on the TSs of composition 5 with 10% LS content. An increase of LS content to 15 and 20% (compositions 6 and 7) leads to a decrease in density at all temperatures, possibly caused by the increasing amount of organic components from LS in the initial mixtures. This general trend matches that observed with other mechanical properties of these novel ceramics, as discussed previously. 3.4. Physicochemical processes of structure formation
Fig. 6. Apparent specific density of the ceramics after sintering at different temperatures.
patterns: as-supplied TM without LS (Fig. 1) at room temperature and composition 7 with 80% TM and 20% of LS content (Fig. 7) sintered at 1150 C. This comparison indicates the complete disappearance of peaks corresponding to crystalline illite (K,H3O) Al2(Si3Al)O10(H2O,OH)2 because of the destruction of its crystalline structure and appearance of the peaks corresponding to crystalline mullite Al6Si2O13, The transformation of quartz SiO2 structures into cristobalite SiO2 structures was also detected. Fig. 7 illustrates the increase in amorphous background intensity that confirms of the generation of amorphous substances during sintering. It is possible that some chemical components of the destroyed illite crystalline structure were absorbed through the synthesis of a considerable amount of cristobalite and amorphous substances. Some oxides, such as TiO2, Al2O3 or Fe3O4, are well-known fluxes. All of these fluxes are present in high quantities in the chemical and mineral compositions (Tables 1e3) of the raw materials. Therefore, it is likely that their common presence decreased the melting point of illite, which was transformed into an amorphous component within the glassy mass. The consequence of such a transformation was an increase in ceramic strength with increasing sintering temperature. Such changes in mineralogical compositions, as well as an increase in amorphous content, can alter the microstructure of ceramics in ways that enhance mechanical properties. The microstructure of composition 7 sintered at 1150 C (Fig. 8A) does not have the same monolithic character. However, under higher magnification (Fig. 8-B) many particles d albeit not all of them d are observably bonded. This bonding increases flexural strength and demonstrates that chemical interactions occur among particles through partial melting, even though the particles still do
To study the physicochemical processes that controlled structure formation in the ceramics, were compared two diffractogram
Fig. 5. Water absorption (%) of ceramics versus LS content and sintering temperature.
5
Fig. 7. Diffractograms pattern of composition 7 after sintering at 1150 C.
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Fig. 8. Micro-scale morphological structure of ceramics of composition 7 sintered at 1150 C, by SEM method.
not show similarities because they continue to have different sizes, angles, and inter-particle pores. At 5000 magnification, the images confirm that particle melting increased. Many particles lost their original shape and configuration during melting and chemical interaction, agglomerating into large sheets of vitrified (amorphous) material. This mechanism would tend to increase ceramic mechanical strength. SEM results confirmed XRD results that suggested a high content of amorphous material. With increasing temperature, there is improved ordering in the crystalline portion but an overall increase in amorphous content. The chemical compositions (Table 5) determined by EDS microanalysis of six points of Fig. 8-B are quite different, as it is impossible to achieve complete homogenization of the material at the micro-scale during initial mixing of the components. The particles from the initial mixes had no resemblance to crystal forms, and none of the newly formed particles had a constant chemical composition across different parts. It can be concluded that crystals are so rare and small within the new minerals that they have no influence on the mechanical properties of the samples, in contrast to the widespread molten glassy mass that is clearly visible in the micrographs (Fig. 4). These findings can be explained by the inability to achieve complete homogeneity in chemical composition at the micro-scale despite mixing the initial components and sintering for 6 h. The chemical composition of adjacent points of composition 7 after sintering at 1150 C determined by laser micro mass spectrometry (Fig. 9), was similar to the results of the MEV and EDS tests. The combinations of the isotopes and their intensities differ between the A, B and C adjacent points. This fact confirms once more the amorphous nature of the new ceramic structure as also shown by XRD and SEM analyses. 3.5. Environmental properties of developed ceramics The high level of LS toxicity from heavy metals (Table 2) makes it essential to verify whether they are effectively neutralized by sintering. To this end, leaching and solubility tests were performed to Table 5 Chemical microanalysis of locations marked in Fig. 8 A and B, as characterized by EDS. N Point Point Point Point Point Point
1 2 3 4 5 6
C
Na
Mg
Al
Si
S
Ti
Fe
18.04 7.00 9.27 1.93 4.63 0.96
11.95 14.11 8.44 4.72 2.37 5.57
8.15 16.09 10.17 7.36 13.14 0.65
33.48 18.36 25.55 23.87 15.23 38.07
14.73 23.73 33.48 47.53 62.11 40.11
8.14 9.29 3.17 9.18 0.44 8.31
1.28 4.29 9.27 0.68 1.19 0.19
4.23 7.13 0.65 4.73 0.89 6.14
generate an extract from which metal concentration could be measured. Composition 7 with 20% LS content was selected because it had the highest heavy metal content. The temperature 1150 C was chosen as it was the lowest sintering temperature used in this research. The results of the leaching and solubility tests (Table 2) indicate a very low level of contamination within the extract compared with the thresholds set by national standards NBR 15270-3/05 (2005). Comparison with the toxicity of the original LS (Table 2) used as a raw material shows thousands of times less heavy metal content in the extract obtained from the ceramic of composition 7. Thus, dangerous waste produced in the laundering process can be successfully used to improve the mechanical properties of structural ceramics. These results allow the ceramics to be classified as an environmentally friendly building material. At the end of its service as a construction material, it cannot pollute the environment and can be used again as an inert demolition material. This property of a designed material is entirely consistent with the 10th point (Design for Degradation) of the Twelve Principles of Green Chemistry: “Chemical products should be designed so that at the end of their function they break down into innocuous degradation products and do not persist in the environment” (Anastas and Green, 1998).
4. Conclusions 1. Laboratory experiments confirm the feasibility of using cleaning sludge, arising from industrial laundry wastewater and having a high content of oily material, as a raw material to be mixed with red clay for the production of conventional white ceramics. Specifically, the use of sludge from an industrial laundrydone that specializes in extremely polluted industrial uniforms with very high contents of different types of heavy metals, grease, oil and oily components, resin, tar, paints, organic volatile compounds, carbonates, and so ondas a raw material illustrates how hazardous waste can be transformed into an environmentally effective component in ceramic production. 2. The ceramic materials produced in this work had the following physical properties: three-point flexural strength till 15.59 MPa, values of linear shrinkage ranged from 4.52 to 14.06%, water absorption values e from 13.03 to 20.33%, and density values ranged from 1.65 to 1.83 g/cm3. 3. XRD, SEM and LAMMA analyses of the physicochemical processes of the interaction between laundry sludge and sandeclay mix during sintering indicated the destruction of crystalline illite and the synthesis of mainly glassy amorphous substances along with some crystalline mullite and cristobalite.
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7
Fig. 9. Isotopic composition of composition 7 sintered at 1150 C, as measured by method laser micro mass spectrometry (LAMMA).
4. It is reasonable to conclude that hazardous waste from industrial laundry sludge can in fact serve as a valuable component that enhances the mechanical properties of ceramics, reduces poisoning of the environment and decreases the extraction of natural raw materials, thus improving ecological efficiency. Acknowledgments The authors thank the Environmental Technology Laboratory (LTA) and the Laboratory of Mineralogical Analysis (LAMIR) of the Federal University of Paran a (UFPR), and the staff of BOSCH in Curitiba, Brazil, for conducting SEM and EDS analysis in this research work. References Abdul, G., Liew, A.I., Calvin, H.K.W., Abdul, A.S., Megat, J.N.M.M., et al., 2004. Incorporation of sewage sludge in clay brick and its characterization. J. Waste Manag. Res. 22, 226e233. Alqam, M., Jamrah, A., Daghlas, H., 2011. Utilization of cement incorporated with water treatment sludge. Jordan J. Civ. Eng. 5 (2), 268e277. Anastas, P.T., Green, W.J.C., 1998. Chemistry: Theory and Practice. Oxford University Press, New York. Anyakora, N.V., 2013. Characterization and performance evaluation of water works sludge as bricks material. J. Eng. App. Sci. 3 (3), 69e76. Castro, T.M., 2010. Solidification/stabilization of Sludge from Textile Laundry to Manufacture Ceramic Blocks Acoustic: Study of Compression Resistance and Water Absorption. Dissertation. State University of Maringa. Dondi, M., Marsigli, M., Fabbri, B., 1997. Recycling of industrial and urban wastes in brick production: a review (part 2). J. Tile Brick Int 13 (4), 302e309. Herek, L.C., Hori, C.E., Reis, M.H.M., Mora, N.D., Tavares, C.R.G., Bergamasco, R., 2012. Characterization of ceramic bricks incorporated with textile laundry sludge. Cer. Int. 38, 951e959. ^ vel e a John, V.M.J., Angulo, C.S., Zordan, S.E., 2001. Desenvolvimento Sustenta ~o Civil. In: Semina rio desenvolvimento Reciclagem de Resíduos na Construça
~o civil e materiais reciclados e suas sustent avel e a reciclagem na construça ~es, IV (20010 S~ aplicaço ao Paulo. Available at: www.reciclagem.pcc.usp.br/ftp/ artigo%20IV_CT206_2001.pdf (accessed 03.06.06.). n, M.M., 2005. Application of sewage sludge in the manufacturing of ceramic Jorda tile bodies. J. Appl. Clay Sci. 30 (3e4), 219e224. _ R., Kizinievi Kizinievi c, O., Zurauskien e, c, V.R., 2013. Utilization of sludge waste from water treatment for ceramic products Zurauskas. Constr. Build. Mat. 41, 464e473. Leite, B.Z., Pawlowsky, U., 2002. Methodology for waste minimization. J. Braz. Foods Year III 14. Sao Paulo, 31-36. Mahzuz, H.M.A., Alam, R., Alam, M.N., Basak, R., Islam, M.S., 2009. Use of arsenic contaminated sludge in making ornamental bricks. J. Environ. Sci. Technol. 6 (2), 291e298. nchez, C.M.F., Vieira, C.M.F., 2008. Incorporation of Monteiro, S.N., Margem, J.I., Sa sludge waste from water treatment plant into red ceramic. J. Constr. Build. Mater. 14 (3), 1281e1287. Mymrin, V.A., 2012. Industrial and Municipal Wastes Utilization as Economical and Environment Efficient Raw Materials. Available in. http://paginapessoal.utfpr. edu.br/mymrinev. NBR 10004, 2004. Solid Waste e Classification Rio de Janeiro, Brazil. NBR 15270-3/05, 2005. Flexural rupture Strength and Water adsorption Measurement of Ceramic Bricks, Rio de Janeiro. Oliveira, E.M.S., Machado, S.Q., Holanda, J.N.F., 2004. Characterization of waterworks waste (sludge) aiming its use in red ceramic. Cer. Int. 50, 316: 324e330. Pan, C., Sun, J.R., Liaw, K.D., 2001. Reuse of water treatment plant sludge and dam sediment in brick-making. J. Water Sci. Technol. 44 (10), 273e277. ~o de contaminantes de compostos de lodoPietrobon, C.L., et al., 2004. Lixiviaça cimento Maring a. J. Acta Sci. 26 (1), 45e52. Ramirez, Z.R.M., Espesel, A.F., Chavez, G.L., Duran, M.A., Schouwenaars, R., 2008. Optimization of the preparation conditions of ceramic products using drinking water treatment sludges. Valorization of drinking water treatment sludge as raw materials to produce concrete and mortar. Am. J. Environ. Sci. 4, 3,223e228. Richter, C.A., 2004. Treatment of Sludge from Wastewater Treatment Plant. Edgard ~o Paulo. Blücher Ltda, Sa ssio, P., Santos, G.T.A., 2006. Effect of the Teixeira, S.R., Souza, A.S., Souza, N.R., Ale addition of sludge from water treatment plants on the properties of structural ^m. 52 (323), 215e220. ceramic material. J. Cera
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Red ceramics enhancement by hazardous laundry water cleaning sludge Nagalli 1, Rodrigo E. Catai 1, Ronaldo L.S. Izzo 1, Vsevolod Mymrin*, Kirill Alekseev 1, Andre Juliana L. Rose 1, Haroldo A. Ponte 1, Cesar A. Romano 1 , Str. Deputado Heitor de Alencar Furtado, 4900, Campus Curitiba, CEP: 81280Civil Engineering Department of Federal Technological University of Parana , Brazil 340, Ecoville, Parana
a r t i c l e i n f o
a b s t r a c t
Article history: Received 25 July 2015 Received in revised form 17 December 2015 Accepted 19 December 2015 Available online xxx
Permanently increasing number of industrial and municipal wastes accumulated in the dumps, inevitably leads to contamination of soils, surface waters and subterranean waters, the atmosphere and is a perceptible factor of climate change on our planet. This paper is one more proof that waste utilization, as a valuable source of components for new materials production, is environmentally and economically the best way for their management. The purposes of the research were the next: to develop eco-friendly ceramics that include and immobilize hazardous laundry sludge after cleaning of extremely polluted industrial uniforms with high contents of As, Ba, Cd, Pb, Cr, Hg, Cu, Zn and grease, oil, resin, tar, paints, organic volatile compounds, etc.; to improve the mechanical properties of red ceramic, using laundry sludge; to demonstrate a possibility of natural raw materials extraction decrease, partially replacing them with laundry sludge. This sludge was introduced in the traditional clay-sand mix in the amount of 0, 3, 5, 7, 10, 15 and 20 wt. %. After sintering of these composites at temperatures 1000 , 1050 , 1100 , 1150 C the maximum values of flexural strength resistance of the ceramics was 15.6 MPa, values of linear shrinkage ranged from 4.5 to 14.1%, water absorption values e from 13.0 to 20.3%, and density values ranged from 1.65 to 1.83 g/cm3. All these characteristics of the mechanical properties of the developed materials significantly exceed the properties of ceramics from traditional clay-sand mixes without laundry sludge. The leaching and solubility values of the heavy metals immobilized within these ceramics are hundreds of times lower than threshold levels set by the national standards of Brazil. This study showed that industrial laundry sludge can be safely used as additive to ceramics in proportions of 10e20% wt. %, enhancing the mechanical properties of the materials and constituting an ecological way to manage these wastes. © 2015 Elsevier Ltd. All rights reserved.
Keywords: Sintering Composites X-ray methods Chemical properties
1. Introduction Some types of industrial and municipal wastes are extremely hazardous because of their high content of dangerous components, such as concentrated heavy metals. One example is laundry sludge (LS) from extremely polluted industrial uniforms, containing many heavy metals including As, Ba, Cd, Pb, Cr, Hg, Cu, and Zn. Their concentration far exceeds Brazilian toxicity thresholds, and therefore, this type of LS must be classified as hazardous waste. The most
* Corresponding author. Tel.: þ55 41 3279 4518. E-mail address: [email protected] (V. Mymrin). 1 Tel.: þ55 41 3279 4518.
common practice is to discharge this waste directly into landfills (Richter, 2004). There is extensive scientific and technical literature on finding environmentally safe and economical methods to use waste as a raw material (Mymrin, 2012; Pan et al., 2001) including sewage sludge from water cleaning. One of the more widespread methods is the use of waste sludge to produce ceramics (Ramirez et al., 2008; Teixeira et al., 2006; Oliveira et al., 2004). Herek et al. (2012) studied the use of different concentrations of textile laundry sludge for ceramic brick production, and Abdul et al. (2004) used sewage sludge as a raw material in red brick firing. Dondi et al. (1997) classified industrial sewage sludge as a valid material flux in ceramics fabrication, and Leite and Pawlowsky (2002) used it to plastify waste. Mahzuz et al. (2009) developed a method to use n arsenic-contaminated sludge to produce ornamental bricks. Jorda
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(2005) reported that sewage sludge can decrease the bending strength of construction materials. However, other study (Ramirez et al., 2008) showed a positive influence of the sludge on the mechanical properties of concrete and mortar. Pietrobon et al. (2004) came to a neutral conclusion: they reported that the addition of 10%, 20% and 30% of sewage sludge negatively altered the structure of cement, but that the difference was not critical. Additionally, Castro (2010) examined the acoustic properties of ceramic blocks. John et al. (2001) successfully used WTPS as an additive to cement mortars. Kizinievi c et al. (2013) analyzed the influence of WTPS (from 5 to 40 wt. %) on the physical and mechanical properties, structural parameters as well as mineralogical composition of the ceramics sintered at 1000 C and 1050 C. Anyakora (2013) used WTPS by adding 90% of natural clay to produce the brick. Alqam et al. (2011) investigated the use of WTPS (10e50 wt. %) used cement in the production of paving tiles. The researchers of Federal Technological University (UTFPR), Brazil, in the area of civil engineering have fairly extensive experience in developing of new construction materials with extensive use of more than 80 types (Mymrin, 2012) of industrial and municipal wastes as valuable components, which are significantly improving mechanical and chemical properties of these materials. A significant fraction of these wastes are sludge, including the particularly dangerous waste of galvanic sludge. The objectives of this study were as follows: to investigate experimentally the efficiency of using LS from extremely polluted industrial uniforms and possessing a high content of multiple heavy metals, oily wastes and other organic substances; to study the physicochemical process of forming red ceramic structures after composite sintering; and to develop new and environmentally friendly composites for ceramics production, with mechanical properties meeting or exceeding the criteria established by Brazilian technical standards, by using the wastewater sewage sludge from an industrial laundry. As one of the green chemistry principles expresses, wherever practicable, synthetic methods should be designed to use and generate substances that possess little or no toxicity to human health and the environment (Anastas and Green, 1998). In this study, the aim was to include a toxic laundry waste in ceramics production, converting it in a useful material that in this new form does not pose any significant toxicity.
(Brazil). Mechanical resistance was tested using the three-point flexural resistance strength method on an EMIC universal testing machine. The water absorption coefficient by immersion was determined with an Instrutherm BD 200 under the Brazilian NBR 13818/1997 standard. Linear shrinkage of the TS was determined using a digital caliper (DIGIMESS). 2.2. Calculations The flexural rupture strength of the tested specimens (TSs) was measured following standard NBR 15270-3/05 (2005) and using the following equation:
RF ¼ ð3PLÞ= bh2
(1)
where RF is the flexural rupture strength (MPa), P is the maximum load supported by the specimen (kgf), L is the distance between the supports (mm), b is the width of the TS (mm), and h is the height of the TS (mm). Water absorption (WA) was measured according to the Brazilian standard NBR 15270-3/05, (2005), which uses the following equation:
WA ¼ ½ðMSAT MD Þ=MD 100
(2)
where MSAT is the mass of the water-saturated specimen after 24 h of water immersion, and MD is the mass of the dry specimen after sintering. Apparent specific density DA was calculated using the equation
DA ¼ Md=ðMd MwÞ
(3)
where DA e apparent specific density (g/cm3); Md e the weight of the ceramics body in air (g); Mw e mass of the ceramics body immersed in water (g) equal to the volume of immersed specimen (cm3). In accordance with Archimedes' law the weight of a body immersed in the liquid is reduced by the buoyant force acting on the body fluid side; it is equal to the weight of the displaced volume (cm3) of body fluid. 3. Results and discussion
2. Research methods
3.1. Raw materials under study
2.1. Methods
A sample of LS was obtained from the filters of washing machines of the industrial laundry in Curitiba, Brazil, that specializes in cleaning extremely polluted industrial uniforms. Its high calorific value (almost 5300 kcal/kg), density and black color similar to bitumen indicated that these clothes were worn by workers engaged in petroleum extraction and refining. The LS ash content was 28.2%, and the extracted ash mainly consisted (Table 1) of SiO2 (71.5%), Al2O3 (12.74%) and Fe2O3 (8.34%). A very high C.L. (71.8%) was most likely caused by grease, oil and general emulsified oily components, resin, tar, paints, organic volatile compounds, carbonates, and water. A very high content of oily materials precluded
The raw materials and ceramics were characterized using various methods. To determine the chemical composition, a Philips/ Panalytical X-Ray Fluorescence Spectrometer model PW2400 was used. Studies of mineralogical composition using the powder method were performed with a Philips X-Ray Diffractometer, model PW1830, with a monochromatic wavelength lCu-Ka, at 2q range of 2e70 . Morphological structures were determined by scanning electron microscopy (SEM) using an FEI Quanta 200 LV. Chemical microanalyses were determined using energy dispersive spectroscopy (EDS) with an Oxford (Penta FET-125 Precision) X-ACT and by micro-mass analyses using a laser micro-mass analyzer (LAMMA-1000, model X-ACT). The samples of the ceramics with particles diameter <9 mm were washed in deionized water, agitated in solution with pH ¼ 4.8 at 25 C during 18 h and leached extract was separated on a glass fiber filter with a porosity of 0.6e0.8 mm. Leached metals were analyzed using atomic absorption spectrometry method with a Perkin Elmer 4100 spectrometer. Granulometric composition was determined using laser diffraction particle size distribution analysis with a Granulometer CILAS 1064
Table 1 Chemical composition of the raw materials characterized by XRF method. Raw material
LS TM
Concentration, wt.% SiO2
Al2O3
Fe2O3
Na2O
CaO
SO3
MgO
C.L.
71.57 57.50
12.74 19.70
8.34 8.70
1.47 0.10
1.23 0.00
0.87 0.00
1.41 1.40
71.83 7.58
Note: C.L. e calcinations loss.
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V. Mymrin et al. / Journal of Cleaner Production xxx (2016) 1e7
investigation of the as-received LS mineral composition by XRD or of its structure by SEM or EDS. The traditional mix (TM) of red clay with sand was obtained from local brick factory in the region of Mariental, in the state of Paran a, Brazil. TM is a common raw material in brick factories worldwide that has similar principal components to LS (Table 1), but with less SiO2 (57.50%) and more Al2O3 (19.70%). Its value of calcinations loss (CL ¼ 7.58%) can be explained by the organic content of the natural clay. A study of leaching and solubility of liquid LS extract (Table 2) by AAS showed that the content of multiple metals far exceeded Brazilian toxicity thresholds NBR 10004 (2004); therefore, the LS can be classified as hazardous waste. The mineralogical composition of TM, as characterized by XRD (Fig. 1), includes illite (K,H3O)Al2(Si3Al)O10(H2O,OH)2 and quartz SiO2 with a relatively high content of amorphous material. Fig. 2 depicts, under high magnification, the particle morphology of the TM raw material as examined by SEM. These micrographs display a wide variation in particle size and configuration with widely varying inter-particle pore shapes. The EDS analysis (Table 3) of the chemical composition of the TM was consistent with the XRF (Table 1) and XRD (Fig. 1) analysis results. The main inorganic components of the TM were amorphous substances with composition that varied considerably at the microscale. Some clay particles exhibited high Si and Al content, which are present in illite, as well as Fe and minor amounts of other elements. Particles with high Ca content may have consisted of carbonate-containing materials; particles with C content may have included carbonates or organic materials such as wood or plant remains. 3.2. Manufacturing of test samples (TSs) The ceramic TSs were manufactured by mixing and homogenizing the raw materials in different proportions (Table 4), moistening to an optimal humidity (10e12%), compacting at 5 MPa in a rectangular form with dimensions 60 20 10 mm, drying at 100 C for 24 h and sintering for 6 h at 1000 C, 1050 C, 1100 C and 1150 C. The TSs of composition 1 were prepared from TM without the inclusion of LS to serve as standard (control) ceramics. 3.3. Mechanical properties of the developed ceramics The average values and standard deviations of the sintered TSs' mechanical properties were calculated based on ten replications (Fig. 3).
Table 2 Results of leaching and solubility tests of the LS and of composition 7 sintered at 1150 C. Elements
As Ba Cd Pb Cr total Hg Se Al Cu Fe Mn Zn
Leaching, mg/L
Solubility, mg/L
LS
Comp. 7
NBR*
LS
Comp. 7
NBR*
9.92 88.28 9.15 6.32 22.15 2.04 2.75 20.13 23.52 39.63 74.18 78.18
0.21 <0.1 <0.005 <0.01 <0.05 <0.001 e <0.10 <0.05 0.07 e <0.10
1.0 70.0 0.5 1.0 5.0 0.1 1.0 * * * * *
12.44 97.15 17.11 8.56 25.72 3.84 3.74 29.28 33.44 53.87 92.74 92.73
<0.001 <0.1 <0.005 <0.01 <0.05 <0.0002 e <0.10 <0.05 <0.05 e <0.10
0.01 0.7 0.005 0.01 0.05 0.001 0.01 0.2 2.0 0.3 0.1 5.0
Note: NBR* e no threshold of the Brazilian standards NBR 10,004 (2004).
3
Fig. 1. Diffractogram pattern of the TM used in this study.
According to the standard NBR 15270-3/05 (2005), solid bricks can be classified by flexion resistance strength as follows: Class A for <2.5 MPa; Class B for 2.5e4.0 MPa; and Class C for >4.0 MPa. When fired at T ¼ 1000 C, the ceramics with LS content ranging from 3% to 20%, exhibited an increase in flexural strength from 2.80 to 5.96 MPa for compositions ranging from 3% to 15% LS, dropping to 5.44 MPa at 20% LS. For T ¼ 1050 C, an increase from 4.79 to 8.69 MPa was observed for compositions ranging from 3% to 10% LS, followed by a steady decrease to 5.71 and 7.50 MPa as LS content increased to 15% and 20%. As a result of sintering temperature increasing to 1100 C the value of TSs of composition 2 with 3% of LS almost stopped, with 5% (composition 3) decreased for 2.01 MPa (from 8.50 to 6.49 MPa), but of compositions 4e7 with 7, 10, 15 and 20% their values of resistance increased by 9.92, 15.42, 15.09 and 15.59 MPa, i.e. in 1.14, 1.79, 2.64 and 2.08 times correspondingly. The next temperature increasing till 1150 C leaded to the growing up of resistance values of ceramics with 3 and 5% of LS contents (composition 2 and 3) by 3.77 and 5.79 MPa (in 1.75 and 1.89 times), but it caused a sharp drop in strength of all following compositions with 7, 10, 15 and 20% of LS contents by 3.21, 1.30, 2.64 and 3.07 MPa respectively. The ribs of the TSs of these compositions were considerably melted and rounded, especially in compositions 6 and 7. Thus, the maximum flexion resistance strength (15.59 MPa) had TSs of the composition 7 after sintering at T ¼ 1100 C, which is 2.68 times higher than the resistance of control composition 1 only from traditional clay-sand mix without LS content. Such complex trends in the flexural strength values of the ceramics as a function of LS content and sintering temperature can be explained by two mechanisms acting in opposition: 1) an increase in LS content increases the combustion quantity of oily components and other organic substances from the formation and expansion of gases that form a network of pores within the sample. These factors lead to a decrease in strength. 2) A high concentration of heavy metals and alkaline detergents acting as fluxes tends to lower the melting point temperature and alloy TM particles and change the microstructure to a durable glass-like material. The data summarized above on LS content versus firing temperature indicate a transition of predominance from the second factor (strength increasing) to the first (strength decreasing). The very large (till 2.66 times) increase in ceramic strength at 1100 C can be attributed to TM melting and a transition to the durable glassy state. However, the flexion resistance strength increased with increasing LS content in all of the developed ceramics listed in Table 4, and all values significantly exceeded the demands of standards NBR 15270-3/05 (2005). Some researchers (Herek et al., 2012; Monteiro et al., 2008) have reported the opposite effect: a reduction in strength with increasing LS content in sintered ceramics. Three reasons could
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Fig. 2. SEM micrographs of TM with EDS points labeled; chemical compositions are presented in Table 4.
Table 4 Compositions of the TSs, wt%. Raw materials
LS TM
Fig. 3. Three-point flexural strength of ceramics sintering at different temperatures.
explain the contradiction between the current study's results with the results of the previous investigations: 1. Previously reported sintering temperatures did not exceed 1000 C, whereas in the present experiments, the sintering temperature reached 1150 C as a melting point of majority of the compositions under study; 2. The amount of metals present in other groups' LS did not exceed thresholds set by the Brazilian standard. In contrast, leaching and solubility tests of the LS used in this research show that some heavy metals are present in concentrations thousands times higher than the maximum permitted (Table 2). For example, the solubility of Cr is 5144 times higher; the corresponding multiplicative factor for a selection of other elements is 3840 for Hg, 3422 for Cd, 1244 for As, and 856 for Pb. This difference in the degree of contamination of LS arises because the above-mentioned authors likely used sludge from municipal laundries that process relatively clean bedclothes, underclothes, and other household laundry. The sample of LS used here was obtained from an industrial laundry that specializes in washing extremely polluted industrial uniforms with a very high content of all types of heavy metals, grease, oil and oily components, resin, tar, paints, organic volatile compounds, and
N of composites/wt.% content 1
2
3
4
5
6
7
0 100
3 97
5 95
7 93
10 90
15 85
20 80
carbonates, among other toxic materials. Each of these three factors could be expected to change the processes of structure formation of developed ceramics, and their combined effect may be the source of such considerable differences between the experimental results. The standard deviation values of flexural resistance of all ceramics increased with increasing sintering temperature, but in no case did they exceed 7% of the average values. The ceramics showed direct dependence between linear shrinkage of the TSs and sintering temperature (Fig. 4). For all sintering temperatures, control composition 1 always exhibited the least shrinkage, except at 1150 when considerable TM melting occurred. Similar amounts of melting were observed in TSs of compositions 6 and 7 with 15% and 20% LS content. The values of shrinkage slowly increased with decreasing LS content and sintering temperature. The addition of even 3% LS to KC (composition 2) at 1000 increased the shrinkage value by 56.9%. The addition of 5% and 7% LS (compositions 3 and 4) increased shrinkage by only 63.5% and 65.2%, respectively. The TSs of composition 5, the most resistant after sintering at 1150 C increased its value of shrinkage 1.18% (from 9.23 till 10.42%) and lost 1.30 MPa in strength; the most resistant after sintering at 1100 C TSs of composition 7 increased at
Table 3 Chemical composition of TM measured by EDS at the points labeled in Fig. 2-C. Point
1 2 3 4 5 6
Chemical composition, wt. % C
Na
Mg
Al
Si
Ca
Ti
Fe
Total
1.43 3.28 15.01 7.39 5.23 1.16
0.93 1.13 0.18 3.14 2.47 3.25
9.34 7.43 0.96 5.15 14.18 9.32
33.53 24.46 15.63 27.23 17.11 22.32
53.28 31.80 53.19 22.14 31.21 28.85
13.29 29.12 5.03 17.00 15.49 20.10
1.16 0.24 0.43 0.67 0.95 11.27
15.27 2.54 9.57 17.28 13.36 3.73
100.0 100.0 100.0 100.0 100.0 100.0
Fig. 4. Dependence of ceramics' linear shrinkage on LS content and sintering temperature.
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1150 C the shrinkage values for 2.13% with a the loss in strength of 3.07 MPa. This fact can be one of the explanations of the TSs of composition 7 resistance decreasing. The values of the WA of the most part of the compositions (Fig. 5) also increased with increasing of LS content, varying from 16.8 to 20.3% at 1000 C and 13.3e15.5% at 1150 C. Generally, WA values decreased with increasing of sintering temperature. Despite the possibility of closed pore formation, which can mask the influence of the porosity magnitude on WA, it is observed from Fig. 5 that WA increased at the temperature 1000 C considerably between compositions 5 and 6. The TSs sintered at 1150 exhibited increasing WA values by 0.4e0.6% between compositions 2e5; between TSs 5e6 and 7 the increase was 2.4 and 2.6%, respectively. In contrast, after sintering at 1150 C the TSs exhibited not increasing, but decreasing WA values for ceramics 2e3, 4 and 5 by the following amounts: 0.7, 0.9 and 1.2%, with increases observed only in ceramics 6 and 7 in the amounts of 1.2 and 0.9%. Similar increases of WA with sludge incorporation were observed by Herek et al. (2012). The failure of compositions 6 and 7 to follow this trend confirms the hypothesis of a sharp increase in the porosity of ceramics with 15 and 20% LS content. This increase is caused by the increasing influence of gases from the combustion of organic substances on the cohesion of TM particles while they are melting. In spite of this, the water absorption of the TSs at all temperatures is less than that of control samples, which exhibited a relatively high amount of water absorption. This finding illustrates one of the significant advantages of these novel materials compared with their conventional counterparts. The materials satisfied standards by this metric as well (NBR 15270-3/05, 2005). Sample density after sintering at different temperatures was calculated in accordance with Eq. (3). In general, the density values of all ceramics smoothly increased (Fig. 6) from 1.65 till 1.83 g/cm3 with increasing of sintering temperature. Compositions 5e7, with the three highest amounts of LS (10, 15 and 20%), exhibited the largest increase of density values (0.05e0.06 g/cm3) between sintering temperatures 1100 and 1150 C, The highest density for all temperatures was measured on the TSs of composition 5 with 10% LS content. An increase of LS content to 15 and 20% (compositions 6 and 7) leads to a decrease in density at all temperatures, possibly caused by the increasing amount of organic components from LS in the initial mixtures. This general trend matches that observed with other mechanical properties of these novel ceramics, as discussed previously. 3.4. Physicochemical processes of structure formation
Fig. 6. Apparent specific density of the ceramics after sintering at different temperatures.
patterns: as-supplied TM without LS (Fig. 1) at room temperature and composition 7 with 80% TM and 20% of LS content (Fig. 7) sintered at 1150 C. This comparison indicates the complete disappearance of peaks corresponding to crystalline illite (K,H3O) Al2(Si3Al)O10(H2O,OH)2 because of the destruction of its crystalline structure and appearance of the peaks corresponding to crystalline mullite Al6Si2O13, The transformation of quartz SiO2 structures into cristobalite SiO2 structures was also detected. Fig. 7 illustrates the increase in amorphous background intensity that confirms of the generation of amorphous substances during sintering. It is possible that some chemical components of the destroyed illite crystalline structure were absorbed through the synthesis of a considerable amount of cristobalite and amorphous substances. Some oxides, such as TiO2, Al2O3 or Fe3O4, are well-known fluxes. All of these fluxes are present in high quantities in the chemical and mineral compositions (Tables 1e3) of the raw materials. Therefore, it is likely that their common presence decreased the melting point of illite, which was transformed into an amorphous component within the glassy mass. The consequence of such a transformation was an increase in ceramic strength with increasing sintering temperature. Such changes in mineralogical compositions, as well as an increase in amorphous content, can alter the microstructure of ceramics in ways that enhance mechanical properties. The microstructure of composition 7 sintered at 1150 C (Fig. 8A) does not have the same monolithic character. However, under higher magnification (Fig. 8-B) many particles d albeit not all of them d are observably bonded. This bonding increases flexural strength and demonstrates that chemical interactions occur among particles through partial melting, even though the particles still do
To study the physicochemical processes that controlled structure formation in the ceramics, were compared two diffractogram
Fig. 5. Water absorption (%) of ceramics versus LS content and sintering temperature.
5
Fig. 7. Diffractograms pattern of composition 7 after sintering at 1150 C.
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Fig. 8. Micro-scale morphological structure of ceramics of composition 7 sintered at 1150 C, by SEM method.
not show similarities because they continue to have different sizes, angles, and inter-particle pores. At 5000 magnification, the images confirm that particle melting increased. Many particles lost their original shape and configuration during melting and chemical interaction, agglomerating into large sheets of vitrified (amorphous) material. This mechanism would tend to increase ceramic mechanical strength. SEM results confirmed XRD results that suggested a high content of amorphous material. With increasing temperature, there is improved ordering in the crystalline portion but an overall increase in amorphous content. The chemical compositions (Table 5) determined by EDS microanalysis of six points of Fig. 8-B are quite different, as it is impossible to achieve complete homogenization of the material at the micro-scale during initial mixing of the components. The particles from the initial mixes had no resemblance to crystal forms, and none of the newly formed particles had a constant chemical composition across different parts. It can be concluded that crystals are so rare and small within the new minerals that they have no influence on the mechanical properties of the samples, in contrast to the widespread molten glassy mass that is clearly visible in the micrographs (Fig. 4). These findings can be explained by the inability to achieve complete homogeneity in chemical composition at the micro-scale despite mixing the initial components and sintering for 6 h. The chemical composition of adjacent points of composition 7 after sintering at 1150 C determined by laser micro mass spectrometry (Fig. 9), was similar to the results of the MEV and EDS tests. The combinations of the isotopes and their intensities differ between the A, B and C adjacent points. This fact confirms once more the amorphous nature of the new ceramic structure as also shown by XRD and SEM analyses. 3.5. Environmental properties of developed ceramics The high level of LS toxicity from heavy metals (Table 2) makes it essential to verify whether they are effectively neutralized by sintering. To this end, leaching and solubility tests were performed to Table 5 Chemical microanalysis of locations marked in Fig. 8 A and B, as characterized by EDS. N Point Point Point Point Point Point
1 2 3 4 5 6
C
Na
Mg
Al
Si
S
Ti
Fe
18.04 7.00 9.27 1.93 4.63 0.96
11.95 14.11 8.44 4.72 2.37 5.57
8.15 16.09 10.17 7.36 13.14 0.65
33.48 18.36 25.55 23.87 15.23 38.07
14.73 23.73 33.48 47.53 62.11 40.11
8.14 9.29 3.17 9.18 0.44 8.31
1.28 4.29 9.27 0.68 1.19 0.19
4.23 7.13 0.65 4.73 0.89 6.14
generate an extract from which metal concentration could be measured. Composition 7 with 20% LS content was selected because it had the highest heavy metal content. The temperature 1150 C was chosen as it was the lowest sintering temperature used in this research. The results of the leaching and solubility tests (Table 2) indicate a very low level of contamination within the extract compared with the thresholds set by national standards NBR 15270-3/05 (2005). Comparison with the toxicity of the original LS (Table 2) used as a raw material shows thousands of times less heavy metal content in the extract obtained from the ceramic of composition 7. Thus, dangerous waste produced in the laundering process can be successfully used to improve the mechanical properties of structural ceramics. These results allow the ceramics to be classified as an environmentally friendly building material. At the end of its service as a construction material, it cannot pollute the environment and can be used again as an inert demolition material. This property of a designed material is entirely consistent with the 10th point (Design for Degradation) of the Twelve Principles of Green Chemistry: “Chemical products should be designed so that at the end of their function they break down into innocuous degradation products and do not persist in the environment” (Anastas and Green, 1998).
4. Conclusions 1. Laboratory experiments confirm the feasibility of using cleaning sludge, arising from industrial laundry wastewater and having a high content of oily material, as a raw material to be mixed with red clay for the production of conventional white ceramics. Specifically, the use of sludge from an industrial laundrydone that specializes in extremely polluted industrial uniforms with very high contents of different types of heavy metals, grease, oil and oily components, resin, tar, paints, organic volatile compounds, carbonates, and so ondas a raw material illustrates how hazardous waste can be transformed into an environmentally effective component in ceramic production. 2. The ceramic materials produced in this work had the following physical properties: three-point flexural strength till 15.59 MPa, values of linear shrinkage ranged from 4.52 to 14.06%, water absorption values e from 13.03 to 20.33%, and density values ranged from 1.65 to 1.83 g/cm3. 3. XRD, SEM and LAMMA analyses of the physicochemical processes of the interaction between laundry sludge and sandeclay mix during sintering indicated the destruction of crystalline illite and the synthesis of mainly glassy amorphous substances along with some crystalline mullite and cristobalite.
Please cite this article in press as: Mymrin, V., et al., Red ceramics enhancement by hazardous laundry water cleaning sludge, Journal of Cleaner Production (2016), http://dx.doi.org/10.1016/j.jclepro.2015.12.075
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7
Fig. 9. Isotopic composition of composition 7 sintered at 1150 C, as measured by method laser micro mass spectrometry (LAMMA).
4. It is reasonable to conclude that hazardous waste from industrial laundry sludge can in fact serve as a valuable component that enhances the mechanical properties of ceramics, reduces poisoning of the environment and decreases the extraction of natural raw materials, thus improving ecological efficiency. Acknowledgments The authors thank the Environmental Technology Laboratory (LTA) and the Laboratory of Mineralogical Analysis (LAMIR) of the Federal University of Paran a (UFPR), and the staff of BOSCH in Curitiba, Brazil, for conducting SEM and EDS analysis in this research work. References Abdul, G., Liew, A.I., Calvin, H.K.W., Abdul, A.S., Megat, J.N.M.M., et al., 2004. Incorporation of sewage sludge in clay brick and its characterization. J. Waste Manag. Res. 22, 226e233. Alqam, M., Jamrah, A., Daghlas, H., 2011. Utilization of cement incorporated with water treatment sludge. Jordan J. Civ. Eng. 5 (2), 268e277. Anastas, P.T., Green, W.J.C., 1998. Chemistry: Theory and Practice. Oxford University Press, New York. Anyakora, N.V., 2013. Characterization and performance evaluation of water works sludge as bricks material. J. Eng. App. Sci. 3 (3), 69e76. Castro, T.M., 2010. Solidification/stabilization of Sludge from Textile Laundry to Manufacture Ceramic Blocks Acoustic: Study of Compression Resistance and Water Absorption. Dissertation. State University of Maringa. Dondi, M., Marsigli, M., Fabbri, B., 1997. Recycling of industrial and urban wastes in brick production: a review (part 2). J. Tile Brick Int 13 (4), 302e309. Herek, L.C., Hori, C.E., Reis, M.H.M., Mora, N.D., Tavares, C.R.G., Bergamasco, R., 2012. Characterization of ceramic bricks incorporated with textile laundry sludge. Cer. Int. 38, 951e959. ^ vel e a John, V.M.J., Angulo, C.S., Zordan, S.E., 2001. Desenvolvimento Sustenta ~o Civil. In: Semina rio desenvolvimento Reciclagem de Resíduos na Construça
~o civil e materiais reciclados e suas sustent avel e a reciclagem na construça ~es, IV (20010 S~ aplicaço ao Paulo. Available at: www.reciclagem.pcc.usp.br/ftp/ artigo%20IV_CT206_2001.pdf (accessed 03.06.06.). n, M.M., 2005. Application of sewage sludge in the manufacturing of ceramic Jorda tile bodies. J. Appl. Clay Sci. 30 (3e4), 219e224. _ R., Kizinievi Kizinievi c, O., Zurauskien e, c, V.R., 2013. Utilization of sludge waste from water treatment for ceramic products Zurauskas. Constr. Build. Mat. 41, 464e473. Leite, B.Z., Pawlowsky, U., 2002. Methodology for waste minimization. J. Braz. Foods Year III 14. Sao Paulo, 31-36. Mahzuz, H.M.A., Alam, R., Alam, M.N., Basak, R., Islam, M.S., 2009. Use of arsenic contaminated sludge in making ornamental bricks. J. Environ. Sci. Technol. 6 (2), 291e298. nchez, C.M.F., Vieira, C.M.F., 2008. Incorporation of Monteiro, S.N., Margem, J.I., Sa sludge waste from water treatment plant into red ceramic. J. Constr. Build. Mater. 14 (3), 1281e1287. Mymrin, V.A., 2012. Industrial and Municipal Wastes Utilization as Economical and Environment Efficient Raw Materials. Available in. http://paginapessoal.utfpr. edu.br/mymrinev. NBR 10004, 2004. Solid Waste e Classification Rio de Janeiro, Brazil. NBR 15270-3/05, 2005. Flexural rupture Strength and Water adsorption Measurement of Ceramic Bricks, Rio de Janeiro. Oliveira, E.M.S., Machado, S.Q., Holanda, J.N.F., 2004. Characterization of waterworks waste (sludge) aiming its use in red ceramic. Cer. Int. 50, 316: 324e330. Pan, C., Sun, J.R., Liaw, K.D., 2001. Reuse of water treatment plant sludge and dam sediment in brick-making. J. Water Sci. Technol. 44 (10), 273e277. ~o de contaminantes de compostos de lodoPietrobon, C.L., et al., 2004. Lixiviaça cimento Maring a. J. Acta Sci. 26 (1), 45e52. Ramirez, Z.R.M., Espesel, A.F., Chavez, G.L., Duran, M.A., Schouwenaars, R., 2008. Optimization of the preparation conditions of ceramic products using drinking water treatment sludges. Valorization of drinking water treatment sludge as raw materials to produce concrete and mortar. Am. J. Environ. Sci. 4, 3,223e228. Richter, C.A., 2004. Treatment of Sludge from Wastewater Treatment Plant. Edgard ~o Paulo. Blücher Ltda, Sa ssio, P., Santos, G.T.A., 2006. Effect of the Teixeira, S.R., Souza, A.S., Souza, N.R., Ale addition of sludge from water treatment plants on the properties of structural ^m. 52 (323), 215e220. ceramic material. J. Cera
Please cite this article in press as: Mymrin, V., et al., Red ceramics enhancement by hazardous laundry water cleaning sludge, Journal of Cleaner Production (2016), http://dx.doi.org/10.1016/j.jclepro.2015.12.075