beidellite composite materials

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JECE 770 1–8 Journal of Environmental Chemical Engineering xxx (2015) xxx–xxx

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Journal of Environmental Chemical Engineering journal homepage: www.elsevier.com/locate/jece

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Color removal from anaerobic/aerobic treatment effluent of bakery yeast wastewater by polyaniline/beidellite composite materials

3

Erhan Gengec*

4

Department of Environmental Protection, University of Kocaeli, Turkey

A R T I C L E I N F O

A B S T R A C T

Article history: Available online xxx

The adsorption technique is widely applied for the removal of pollutants from wastewater, especially for toxic or non-biodegradable wastewater. In recent years, the production of alternative adsorbents to replace costly adsorbents has been paid more attention to in literature. Polyaniline/beidellite (PAn + Bei) composite material as an absorbent, which is efficient and low cost can easily be prepared via H2SO4, KIO3 and aniline. This paper deals with color and total organic carbon (TOC) removal of biologically treated bakery yeast wastewater (BYW) using the PAn + Bei composite material by adsorption processes. The effects of experimental variables were chosen as the initial pH (pHi), sorbent dosage (ms), contact time (tc) and mixing speed (s) by a batch sorption process. It was found that by increasing the adsorbent dosage (0.025–0.400 g/50 ml of composite dosage), contact time (2–240 min) and decreasing the pHi (9–3) improved the color and TOC removal efficiencies. The optimum color and TOC removal efficiencies were obtained as 88.7% and 63.3% at 0.400 g/50 ml of adsorbent dosage, a pHi of 3, 240 rpm, and 240 min. In addition, a pseudo-second order kinetic model was proposed to correlate the experimental data. To understand the removal mechanism and characterize the surface of the PAn + Bei composite material, size exclusion chromatography (SEC), BET surface analysis, fourier transform infrared spectroscopy (FTIR) analysis, scanning electron microscope (SEM), thermal gravimetric analysis (TGA), and differential scanning calorimetry (DSC) were employed. As a consequence, the proposed mechanism for the removal by PAn+Bei composite material seems to be driven by an ion exchange process. ã 2015 Published by Elsevier Ltd.

Keywords: Bakery yeast wastewater Beidellite Polyaniline composite Adsorption

5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

1. Introduction Baker’s yeast production by fermentation uses molasses as a raw material which is a by-product of the sugar industry. Due to the molasses, baker’s yeast wastewater (BYW) has a high organic content and dark brown color. Melanoidins are the source of this dark brown color in BYW which is resistant to biodegradation. Melanoidins restrict the sunlight and make a reduction in the natural photochemical process for self-purification of the surface waters [1,2]. Various treatment methods such as a biological process (anaerobic, aerobic), physico-chemical treatment (adsorption, membrane process, reverse osmosis, coagulation/flocculation, electrocoagulation) and oxidation processes (ozone, Fenton) have been performed for the treatment of BYW [3,4]. Nowadays biological treatment of BYW is realized by combinations of anaerobic digestion and aerobic systems that successfully reduce

* Corresponding author: Fax: +90 262 3513629. E-mail address: [email protected] (E. Gengec).

BOD and COD to acceptable limits, but do not deal effectively with the dark color and limits the reuse/recycling of the process water. Treatment by oxidation technology is generally effective on the color, but not COD, membrane filtration processes are prone to fouling [5,6], and reverse osmosis generates a high salinity that presents disposal difficulties [7]. Coagulation removes color and COD effectively, but possesses a number of drawbacks such as necessities for high quantity of inorganic coagulants. Decolorization through chemical treatment by ozone, Fenton’s reagent and H2O2/UV lead to temporary color reduction because of the transformation of the chromophores [8–11]. For these reasons, the BYW requires an alternative treatment technology which is relatively simple and effective in the removal of color before its safe disposal into the environment. Adsorption techniques are widely used to remove pollutants from the water, especially those that are toxic and not easily biodegradable. The studies focused on the production of alternative adsorbents to replace the costly ones reported in literature. Attention has focused on composite materials which are generally produced with various natural solids such as beidellite, cheap natural clay, and polymeric materials like polyaniline (PAn) for the effective removal of

http://dx.doi.org/10.1016/j.jece.2015.09.009 2213-3437/ ã 2015 Published by Elsevier Ltd.

Please cite this article in press as: E. Gengec, Color removal from anaerobic/aerobic treatment effluent of bakery yeast wastewater by polyaniline/beidellite composite materials, J. Environ. Chem. Eng. (2015), http://dx.doi.org/10.1016/j.jece.2015.09.009

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E. Gengec / Journal of Environmental Chemical Engineering xxx (2015) xxx–xxx

pollutants when compared with other polymeric materials. PAn has a large variety of advantages such as high removal efficiencies, low cost, easy synthesis, both chemically (powder form) and electrochemically (a film), and environmental stability. Thus, studies have focused on the production of PAn coated different composite materials recently [12,13]. In literature, sawdust [14–17], rice husk and saw dust of Eucalyptus camaldulensis [18], palygorskite [19], montmorrillonite [20], silica gel [21] were coated by polyaniline for the removal of pollutants from water/wastewater. The novelty of this study is the production of a new composite material by coating beidellite with aniline to use it for color and TOC removal of biological treated baker’s yeast wastewater for the first time. The effects of the variables such as initial pH (pHi), sorbent dosage (ms), contact time (tc) and mixing speed (s) on the adsorption were examined by using a batch method. Several kinetic mechanisms were applied on data and molecular weight distributions (MWDs) were monitored during treatment by SEC. SEM, TGA, BET surface analysis, DSC, and FTIR were used to characterize the PAn + Bei composite materials. 2. Materials and methods 2.1. Preparation of beidellite/polyaniline composite Beidellite is a dioctahedral smectite named after Beidell, CO, USA. Large deposits of beidellite minerals were explored in different locations of Turkey [22]. It was used for daily cleaning processes in the Black Sea region of Turkey. PAn is a poly aromatic amine that can be easily synthesized chemically from Brønsted acidic aqueous solutions. It is one of the most potentially conducting polymers and has obtained considerable attention in recent years. Chemical polymerization of aniline in aqueous acidic media (Brønsted acid) can easily be performed by the use of chemical oxidizing agents such as (NH)4S2O8, KIO3 and K2Cr2O7 as shown in Fig. 1 [23]. There are a few studies regarding the production of polyaniline composites material in which different coated material, oxidizer, acid types and production processes were used. Ansari [14] and Ghorbani et al. [24], have produced different polyaniline composite materials by similar production processes with this study. Ghorbani et al. [24], produced the polyaniline and polypyrrole composites material for treatment of a real wastewater, paper mill wastewater, and the results showed that polyaniline/polypyrrole composite material have an important potential for using pollutants from real wastewater. In this study, preliminary studies were realized according to literature, then the production conditions of Ansari [14] and Ghorbani et al., were modified for production of PAn + Bei composite materials. For preparation of composite materials, 1 g of beidellite was added to 100 ml H2SO4 (1 M) solution and the solution was mixed at a stirring rate of 500 rpm [25]. Then, 1 g KIO3 was added at room temperature and 1 ml of aniline monomer was injected slowly. The polymerization was carried out at room temperature for 2 h.

n

NH2

H2SO4 Oxidation

NH

NH

In order to remove the unreacted monomers and oxidants, the final product was washed thoroughly with 500 ml of deionized water. Then, the product was dried at 60
C for 24 h. The beidellite was used as received without any pretreatment.

92

2.2. Experimental set-up and analytical methods

96

The anaerobic-aerobic treated wastewater was obtained from the baker yeast production industry in Turkey and batch adsorption tests were carried out in a NUVE ST-402 model shaker. TOC levels were determined through combustion of the samples at 680
C using a non-dispersive IR source (Shimadzu, TOC-L model). The pH of the sample was adjusted with H2SO4 or NaOH and measured by a pH meter (WTW Inolab pH 720) and the color of the wastewater was measured utilizing a UV–Vis spectrophotometer at 475 nm (PerkinElmer 550 SE). JEOL 6.060 type scanning electron microscopy (SEM) was used to obtain SEM images. The FTIR spectra of the beidellite and PAn + Bei composite material were recorded on a PerkinElmer Spectrum 100. The TGA curves were performed on a Mettler Toledo TGA 1 Star Sytem at a heating rate of 15
C/min from room temperature to 1000
C. For DSC analysis, a Mettler Toledo DSC1 instrument was used. The BET surface area was measured from the N2 adsorption/desorption isotherms with a Micromeritics ASAP 2010 analyzer (US). The MWD was determined using HPSEC with a Hewlett–Packard HPLC 1100-series system equipped with a refractive index (RI) detector, a diode array detector (DAD) and two ultrahydrogel (Waters, Product Number: WAT011535 and WAT011525) columns. RID measures change in refractive index and its unit was called “Refractive Index Units (nRIU)”. DAD is a type of UV–vis detector and its unit was named as absorbance unit (AU) at any wavelength. Deionized water at a flow rate of 1 ml/min was used as the mobile phase. The results were calibrated using 1 g/l of polyethylene oxide with different molecular weights (25.3, 44.0, 78.3, 152.0 and 326.0 kDa). The weight-average molecular weight (Mw) and number-average molecular weight (Mn) were calculated from the data using the following equations [26] and these calculations were processed by ChemStation software. X ni M2i ð1Þ Mw ¼ Xi nM i i i

97

X nM i i i Mn ¼ X ni

93 94 95

98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128

ð2Þ

Mi and ni are the molecular weight and the height of each ith fraction eluted at the ith volume in the chromatogram, respectively. The polydispersity index (PDI) or heterogeneity index, is a measure of the distribution of molecular mass in a given polymer sample. PDI is calculated from Mw/Mn.

NH

SO4-2

NH SO4-2

n Fig. 1. Overall polymerization reaction of polyaniline [23].

Please cite this article in press as: E. Gengec, Color removal from anaerobic/aerobic treatment effluent of bakery yeast wastewater by polyaniline/beidellite composite materials, J. Environ. Chem. Eng. (2015), http://dx.doi.org/10.1016/j.jece.2015.09.009

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2.3. Adsorption kinetics

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The percentage removal of TOC and the adsorption capacity of adsorbents (mg/g) were calculated using the following relationships:   100 C i  C f ð3Þ TOC removalð%Þ ¼ Ci

135 136

 Ci  Cf V The adsorption capacity of adsorbents; qe ¼ m 138 137 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153

155 154 156 157 158 159 160 161

2.3.1. The pseudo-first-order equation A pseudo-first-order equation can be expressed in a linear form as:

165

166

k1 t 2:303

ð5Þ

where qe and qt are the amount of TOC adsorbed (mg/g) on the adsorbents at the equilibrium and at time t, respectively, and k1 is the rate constant of adsorption (min1). Values of k1 were calculated from the plots of log(qe–qt) versus t. 2.3.2. The pseudo-second-order equation The pseudo-second-order adsorption kinetic rate equation is expressed as dqt ¼ k2 ðqe  qt Þ2 dt

163 162 164

ð4Þ

where m is the mass of PAn + Bei (g), V(l) is the volume of wastewater. Ci and Cf are the initial and final concentrations (in mg/l) of TOC, respectively. The study of adsorption kinetics describes the solute uptake rate and evidently this rate controls the residence time of adsorbate uptake at the solid–solution interface. The adsorption rate constants for the TOC removal were calculated by using pseudo-first order, second-order and intraparticle diffusion kinetic models [27] which were used to describe the mechanism of the adsorption. The accord between the experimental data and the model-predicted values were expressed by the correlation coefficients (R2). A relatively high R2 value indicates that the model successfully describes the kinetics of the adsorption.

logðqe  qt Þ ¼ logðqe Þ 

where qe is the amount of TOC adsorbed at equilibrium (mg/g). The second-order rate constants were used to calculate the initial sorption rate, h ¼ k2 q2e . Values of k2 and qe were calculated using the intercept and the slope of the linear plots of t/qt versus t.

167

2.3.3. Intraparticle diffusion The rate constant for intraparticle diffusion (kid) is calculated using following equation:

171

q ¼ kid t1=2 þ C i



ð6Þ

where k2 is the rate constant of pseudo-second-order adsorption (g/mg min). By integrating and applying the initial conditions, we have a linear form as:   t 1 1 þ ðtÞ ð7Þ ¼ qt k2 q2e qe

3

168 169 170

172 173

ð8Þ

where q is the amount TOC adsorbed (mg/g) at time (t), kid (mg/g min1/2) is the rate constant for intraparticle diffusion and Ci is the thickness of the boundary layer. The values of kid were calculated from the slope of the linear plots of q versus t1/2 [28,29].

175 174 176

3. Results and discussion

179

3.1. Morphology and characterization

180

In this study, a scanning electron microscope (SEM) was used to characterize the surface of the PAn + Bei composite material at a very high magnification and an accelerating voltage of 15 kV. Samples were coated with gold using a sputter coater with conductive materials to improve the quality of the micrograph. The morphology of beidellite and PAn + Bei composite material was illustrated in Fig. 2. The coating by conducting polymer by surface polymerization was very visible. The BET specific surface area, Langmuir surface area and adsorption average pore width were calculated as 66.53, 89.48 m2/g, and 4.95 nm for beidellite and 16.12, 22.74 m2/g, and 17.94 nm for PAn + Bei composite material. During polymerization, some of the pores in the beidellite were stocked by PAn particles, so PAn + Bei had a smaller surface area than beidellite. Small surface areas and higher removal efficiencies by PAn + Bei showed that the removal mechanism by PAn+Bei depended on the ions exchange process. In literature, the main removal mechanism by polyaniline composite materials was reported as the ions exchange process [14,30–33]. The chemical structure of the composite material was determined by FTIR spectrum (Fig. 3) which was a significant tool to distinguish the characteristics of the functional groups. Small amounts of silica species such as amorphous material or quartz were indicated by the presence of a minor band around 836 cm1. The octahedral Al OH groups in the beidellite structures were reported around 911 cm1. The infrared spectra of the beidellite were very similar in the Si O region around 1000 cm1. The interlayer water in the beidellite samples was characterized by an H2O bending vibration at 1635 cm1. The shoulder around 3240 cm1 was ascribed to interlayer H2O chemically bound or coordinated to the interlayer cation. The band at about 3618 cm1

181

Fig. 2. SEM images of (a) beidellite and (b) PAn + Bei composite material.

Please cite this article in press as: E. Gengec, Color removal from anaerobic/aerobic treatment effluent of bakery yeast wastewater by polyaniline/beidellite composite materials, J. Environ. Chem. Eng. (2015), http://dx.doi.org/10.1016/j.jece.2015.09.009

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983 792

0.5

1002

Beidellite PAn+Bei

Absorbance

0.4

1127 1486

0.3

911

1243

1558 836

0.2

0.1

3618

1635

3240

0.0 4000

3500

3000

2500

2000

1500

1000

-1

Wavenumbers (cm ) Fig. 3. FTIR spectra of (a) beidellite and (b) PAn + Bei composite.

100

96

92

88

84

Beidellite 80 100

200

300

400

500

600

700

800

900

1000

Temperature (0C)

100

3.2. Effect of variables on removal efficiencies

252

In the adsorption process, pHi, pollutant concentration, pollutant types, temperature, adsorbent dosage, operating time, mixing speed, particle size are some of the effective process parameters. In this study, the effects of pHi, adsorbent dosage, mixing speed, and operating time were investigated on color and TOC removal efficiencies as discussed below. pH is one of the important parameters that affect the interaction between the adsorbent and adsorbate [37]. In addition, pHi affected the polymerization degree of melanodins which was

253

5

0

80 70 PAn+Bei 60

H e a t F lo w ( m V )

90

50.1 %

218

4.0 %

217

9.5 %

216

5.5 %

215

219

4.9 %

214

of the beidellite was assigned as stretching vibrations of structural OH groups. The small sharp band at 1633 cm1 in the beidellite was due to HO H bending vibrations from adsorbed water [34]. The characteristic absorption peak of AlO Si for Beidellite was observed at 983 cm1, which merged into a strong peak at 1127 cm1 of PAn + Bei [35]. The peaks at 792, and 1243 cm1 were reported as C H out of plane, and C¼N stretching vibrations,

We ig h t ( %)

213

Weight (%)

212

respectively [18]. The peaks at 1558 and 1486 cm1 for PAn+Bei were usually representative of the C¼C stretching vibrations of quinine and benzene rings [24,35]. On the other hand, the peak at 1296 cm1 was correspondent to the C N stretching vibration [24]. The FTIR analysis confirmed that PAn was successfully grafted on the surface of beidellite. TGA curves for beidellite, and PAn + Bei were presented in Fig. 4. There were three main mass loss steps observed for beidellite. The first mass loss (5.5 wt%) occurring from room temperature to 100
C was related to the loss of adsorbed water. Between 100 and 200
C, a maximum weight loss (9.5 wt%) was realized, attributed to the removal of interlayer water and the onset of dehydroxylation. The dehydroxylation reached a low level of loss (4.0 wt%) between 400 and 750
C. Similarly, TGA curves for PAn + Bei showed the weight loss of 4.9% up to 100
C due to the presence of moisture. The weight loss (50.1 wt%) between 100 and 1000
C mainly corresponded to the removal of interlayer water, the dehydroxylation and the decomposition of polymer coverage on the beidellite. The presence of excess water in beidellite and PAn + Bei was also confirmed by the FTIR spectrum. The differential scanning calorimetry (DSC) curve (Fig. 5) showed that an endothermic reaction took place between 50 and 250
C corresponding to water loss from the beidellite surface and interlayered space. On the other hand, there were three different conditions observed for PAn + Bei; an endothermic reaction between 50 and 140
C, an exothermic between 140 and 314
C, and an endothermic reaction between 314 and 400
C. The endothermic reaction between 50 and 140
C corresponded to water loss from the surface and the interlayered space of composite material was observed. The presence of PAn caused an exothermic reaction between 140 and 314
C and above 314
C a second endothermic reaction was present corresponding to the beginning of the collapse of the interlayered structure [36].

-5

-10 PAn+Bei Beidellite

-15

50

-20 40 100

200

300

400

500

600

700

800

900

0

Temperature ( C) Fig. 4. TGA curves (a) beidellite and (b) PAn + Bei composite.

1000

-25 0

50

100

150

200

250

300

350

400

0

Temperature ( C) Fig. 5. Differential scanning calorimetric analysis of beidellite and PAn + Bei.

Please cite this article in press as: E. Gengec, Color removal from anaerobic/aerobic treatment effluent of bakery yeast wastewater by polyaniline/beidellite composite materials, J. Environ. Chem. Eng. (2015), http://dx.doi.org/10.1016/j.jece.2015.09.009

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80 70

50 40 30 pH 3 pH 4 pH 5 pH 6 pH 7 pH 9

20 10 0 0

20

40

60

80

100

120

140

Time (min) 25

TOC Removal (%)

20


15

90

10

80

pH 3 pH 4 pH 5 pH 6 pH 7 pH 9

5

0 0

20

40

60

80

100

120

140

Time (min)

Color Removal (%)

Color Removal (%)

60

Fig. 6. Effects of pHi on color and TOC removals (conditions: ms; 0.1 g/50 ml, tc; 120 min, and s; 240 rpm).

70 60 0.025 g/50 ml 0.05 g/50 ml 0.1 g/50 ml 0.3 g/50 ml 0.4 g/50 ml

50 40 0 0

263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284

the source of color in BYW. Decreasing pH caused a decrease of color intensity [38]. Thus, the treatment of BYW was examined at different pHi and the results were presented in Fig. 6. The results showed that the removal of BYW by PAn + Bei composite material was higher in acidic conditions than those in neutral and alkaline. In literature, two possible pollutants removal mechanism were reported via polyaniline composite materials. If wastewater contains positive ions, the effective removal was realized under neutral and alkaline conditions [15,16]. On the other hand, if wastewater contains negative ions, the effective removal was realized under acidic conditions [18]. Under acidic conditions the nitrogen atom present in the PAn + Bei composite material was protonated. As a result, the higher adsorption behavior of the composite was explained by the electrostatic interaction between this protonated polymer and pollutants. However, as the pH increased (5–9) deprotonation of nitrogen atoms occurred leading to the depletion of active sites in the polymer skeleton. Therefore, the interaction of composite with the pollutant molecule was hindered and consequently results were in the lower adsorption. This result is in agreement with literature [18,37,39]. As seen in Fig. 3, when pHi was increased from 3 to 9, the removal efficiencies decreased from 82.6% to 24% for color and from 21.8% to 6.5% for TOC. The arrangement of wastewater for

20

40

60

80

100

120

Time (min)

40

TOC Removal (%)

262

5

30

20

10 0.025 g/50ml 0.05 g/50 ml 0.1 g/50ml 0.3 g/50ml 0.4 g/50ml

0

0

20

40

60

80

100

120

Time (min) Fig. 7. Effects of the adsorbent dosage on color and TOC removals (condition: pHi; 3, tc; 120 min, and s; 240 rpm).

Please cite this article in press as: E. Gengec, Color removal from anaerobic/aerobic treatment effluent of bakery yeast wastewater by polyaniline/beidellite composite materials, J. Environ. Chem. Eng. (2015), http://dx.doi.org/10.1016/j.jece.2015.09.009

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80 75

Color Removal (%)

70 65 60 80 rpm 120 rpm 160 rpm 240 rpm

55 50 10 0 0

20

40

60

80

100

120

Time (min) 30

TOC Removal (%)

25 20 15 10 80 rpm 120 rpm 160 rpm 240 rpm

5 0

3.3. Kinetic studies and intra-particle diffusion models

310

In this study, pseudo-first order, pseudo-second order and the intraparticle diffusion model were tested with the results to obtain kinetics of the adsorption processes and mass transfer models. The constants and correlation coefficient (R2) values for pseudo-first order, pseudo-second order and intraparticle diffusion model with respect to pHi, ms (g) and s (rpm) were given in Table 1. The linear correlation values close to 1 showed that the model was statistically significant and indicated the applicability of these kinetic equations. All R2 values for pseudo-second order were >96%. However, R2 values for the pseudo-first order and the intraparticle diffusion model were varying at a high range. The data fitting for TOC illustrated that the pseudo-second order model fitted well and suggested chemical sorption as the rate-limiting step of the adsorption mechanism and no involvement of a mass transfer in solution [43]. In literature, the studies which dealt with the preparation of polyaniline composite materials generally focused on the removal of synthetic wastewater. On the other hand, Ghorbani et al. [24], produced the polyaniline composites material for treatment of real wastewater, paper mill wastewater, and reported that the complete removal of COD was not possible by adsorption with polyaniline composite materials. However, Ghorbani and Eisazadeh [44], reported >97% of COD removal for cotton textile wastewater by using polyaniline nanocomposites coated on rice husk ash. These results showed that the composite types and wastewater content affect the removal efficiencies. The best color and TOC removal efficiencies for anaerobic/aerobic treated baker yeast wastewater were reported as 86% and 43% by electrocoagulation process in our previous study [2], which were the similar to the results of this study. This similarity showed that PAn + Bei composite material had an important potential in the treatment of anaerobic/aerobic treated baker yeast wastewater.

311

3.4. The molecular weight distributions of treated BYW

344

The HPSEC method was able to successfully used to detect the MWDs of BYW. In HPSEC, larger molecules move rapidly through the column with eluent and leave the column faster than the smaller ones. The molecular weight distributions of colorful components (Fig. 9) were obtained by the DAD detector and it was clear that there was a remarkable removal of colorful components in wastewater.

345

312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343

-5 0

20

40

60

80

100

120

Time (min) Fig. 8. Effects of the mixing speed on color and TOC removal (conditions: ms; 0.1 g/ 50 ml, pHi; 3, and tc; 120 min). 307 308 309

These results agreed with literature and the removal mechanism by using PAn + Bei composite material seemed to mostly occur via an ion exchange process [16].

Table 1 Pseudo-first order, pseudo-second order and intraparticle diffusion model parameters. Pseudo first order

pHi

ms(g)

S (rpm/min)

a

3 4 5 6 7a 9 0.025 0.05 0.1 0.3 0.4 80 120 160 240

346 347 348 349 350 351

Q1

Pseudo second order

Intraparticle diffusion

qe.cal

k1

R2

qe.exp

q

k2

h

R2

k3

C

R2

5.0 3.1 2.9 1.9 – 1.6 16.4 7.3 4.1 2.4 1.8 3.7 2.7 5.3 7.2

0.029939 0.058727 0.128738 0.034084 – 0.045139 0.029478 0.017273 0.032242 0.048363 0.058036 0.032472 0.054121 0.034315 0.029939

0.855 0.869 0.988 0.851 – 0.877 0.968 0.958 0.939 0.889 0.971 0.96 0.838 0.725 0.855

11.5 10.9 10.2 9.2 – 3.4 19.0 14.3 10.4 7.0 5.6 6.9 6.9 7.9 11.5

3.5 4.7 9.2 10.2 11.1 11.6 22.7 14.3 10.4 6.5 5.6 7.0 7.1 8.1 11.6

0.0891 0.0712 0.0509 0.076 0.052 0.0183 0.0021 0.0085 0.0243 0.0466 0.0653 0.0216 0.0492 0.0249 0.0183

1.11 1.58 4.31 7.92 6.38 2.46 1.07 1.75 2.61 1.98 2.03 1.04 2.45 1.62 2.46

0.999 0.996 0.998 0.999 0.999 0.997 0.998 0.996 0.997 0.986 0.969 0.994 0.999 0.996 0.996

0.9877 0.6147 0.8539 0.2998 0.344 0.3122 2.2238 0.7946 0.752 0.5928 0.3362 0.3572 0.4871 0.9583 1.1573

4.443 7.282 6.758 6.913 2.701 1.554 0.071 5.607 4.982 3.298 3.443 3.125 3.777 2.211 3.957

0.825 0.967 0.994 0.87 0.554 0.95 0.965 0.964 0.95 0.959 0.988 0.958 0.919 0.855 0.804

Satisfactory positive log(qe–qt) values was not available at pH 7.

Please cite this article in press as: E. Gengec, Color removal from anaerobic/aerobic treatment effluent of bakery yeast wastewater by polyaniline/beidellite composite materials, J. Environ. Chem. Eng. (2015), http://dx.doi.org/10.1016/j.jece.2015.09.009

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5

10

15

20

25

30

References

35

20 15

0.4 g PAn+Bei

10

-3 Absorbance (AUx10 )

5 0 20 15 10

0.3 g PAn+Bei

5 0 20 15 10

0.05 g PAn+Bei

5 0 20 15 Raw Wastewater

10 5 0

5

10

15

20

25

30

35

Time (min) Fig. 9. DAD chromatograms of raw wastewater and treated wastewater (AU475nm).

Table 2 Mn, Mw and PDI results at different adsorbent dosage.

Raw wastewater 0.05 g PAn + Bei 0.3 g PAn + Bei 0.4 g PAn + Bei

352 353 354 355

Mn

Mw

D

231.44 176.74 92.61 76.08

4038.4 8129.9 12124.1 13500.1

17.45 45.99 130.91 177.46

In addition, Mw values increased gradually by contrast with Mn, and BYW has the smallest PDI value for raw wastewater (Table 2). These results showed that PAn + Bei composite material preferentially removed the lower molecular weight components.

356

4. Conclusions

357

In this study, beidellite was coated with polyaniline to obtain low cost and effective adsorbent. The effects of pHi, contact time, adsorbent dosage, and mixing speed were studied for the removal performance of the composite material on color and TOC removal efficiencies. The results showed that polyaniline coated beidellite had an important potential for use in wastewater treatment. The optimum color and TOC removal efficiencies were obtained as 88.7% and 63.3% at 0.400 g/50 ml of adsorbent dosage, pHi of 3, 240 rpm, and 240 min. SEC results indicated that the composite material preferentially removed the lower molecular weight components and TOC removal data fitted well to the pseudosecond order. The results of the SEC, SEM, Bet surface area, FTIR analysis and kinetics models showed that the removal mechanism by PAn + Bei composite material was the ion exchange process.

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[1] M. Kobya, E. Gengec, Decolourization of melanoidins by a electrocoagulation process using aluminium electrodes, Environ. Tech. 1–10 (2012) , doi:http://dx. doi.org/10.1080/09593330.2012.671371. [2] E. Gengec, M. Kobya, E. Demirbas, A. Akyol, K. Oktor, Optimization of baker’s yeast wastewater using response surface methodology by electrocoagulation, Desalination 286 (2012) 200–209, doi:http://dx.doi.org/10.1016/j. desal.2011.11.023. [3] D. Pant, A. Adholeya, Biological approaches for treatment of distillery wastewater: a review, Bioresour. Technol. 98 (12) (2007) 2321–2334, doi: http://dx.doi.org/10.1016/j.biortech.2006.09.027. 17092705. [4] Y. Satyawali, M. Balakrishnan, Wastewater treatment in molasses-based alcohol distilleries for COD and color removal: a review, J. Environ. Manage. 86 (3) (2008) 481–497, doi:http://dx.doi.org/10.1016/j.jenvman.2006.12.024. 17293023. [5] Y. Satyawali, M. Balakrishnan, Treatment of distillery effluent in a membrane bioreactor (MBR) equipped with mesh filter, Sep. Purif. Technol. 63 (2) (2008) 278–286, doi:http://dx.doi.org/10.1016/j.seppur.2008.05.008. [6] S.H. Mutl, U. Yetis, T. Gurkan, L. Yilmaz, Decolorization of wastewater of a baker’s yeast plant by membrane processes, Water Res. 36 (3) (2002) 609–616, doi:http://dx.doi.org/10.1016/S0043-1354(01)00252-4. 11827322. [7] S.K. Nataraj, K.M. Hosamani, T.M. Aminabhavi, Distillery wastewater treatment by the membrane-based nanofiltration and reverse osmosis processes, Water 40 (12) (2006) 2349–2356, doi:http://dx.doi.org/10.1016/j. Res. watres.2006.04.022. 16757012. [8] A. Battimelli, D. Loisel, D. Garcia-Bernet, H. Carrere, J.-P. Delgenes, Combined ozone pretreatment and biological processes for removal of colored and biorefractory compounds in wastewater from molasses fermentation industries, J. Chem. Technol. Biotechnol. 85 (7) (2010) 968–975, doi:http://dx.doi. org/10.1002/jctb.2388. [9] M. Peña, M. Coca, G. González, Continuous ozonation of biologically pretreated molasses fermentation effluents, J. Environ. Sci. Health A Tox. Hazard. Subst. Environ. Eng. 42 (6) (2007) 777–783, doi:http://dx.doi.org/10.1080/ 10934520701304450. 17474004. [10] A. Pala, G. Erden, Decolorization of a baker’s yeast industry effluent by Fenton oxidation, J. Hazard. Mater. 127 (1–3) (2005) 141–148, doi:http://dx.doi.org/ 10.1016/j.jhazmat.2005.06.033. 16122871. [11] E.C. Catalkaya, F. Sengül, Application of box-Wilson experimental design method for the photodegradation of bakery’s yeast industry with UV/ H2O2 and UV/H2O2/Fe(II) process, J. Hazard. Mater. 128 (2–3) (2006) 201–207, doi:http://dx.doi.org/10.1016/j.jhazmat.2005.07.052. 16162392. [12] S. Mandal, S.S. Mahapatra, R.K. Patel, Enhanced removal of Cr(VI) by cerium oxide polyaniline composite: optimization and modeling approach using response surface methodology and artificial neural networks, J. Environ. Chem. Eng. 3 (2) (2015) 870–885, doi:http://dx.doi.org/10.1016/j. jece.2015.03.028. [13] E. Igberase, P. Osifo, A. Ofomaja, The adsorption of copper (II) Ions by polyaniline graft chitosan beads from aqueous solution: equilibrium, kinetic and desorption studies, J. Environ. Chem. Eng. 2 (1) (2014) 362–369, doi:http://dx. doi.org/10.1016/j.jece.2014.01.008. [14] R. Ansari, Application of polyaniline and its composites for adsorption / recovery of chromium (VI) from aqueous solutions, Composites (2006) 88–94. [15] R. Ansari, Z. Mosayebzadeh, M. Banimahd keivani, A. Mohammad-khah, Adsorption of cationic dyes from aqueous solutions using polyaniline conducting polymer as a novel adsorbent, J. Adv. Sci. Res. 2 (2011) 27–34. [16] M.S. Mansour, M.E. Ossman, H.A. Farag, Removal of Cd (II) ion from waste water by adsorption onto polyaniline coated on sawdust, Desalination 272 (1–3) (2011) 301–305, doi:http://dx.doi.org/10.1016/j.desal.2011.01.037. [17] J.R. Baseri, P.N. Palanisamy, P. Sivakumar, Application of polyaniline nano composite for the adsorption of acid dye from aqueous solutions, E.-J. Chem. 9 (3) (2012) 1266–1275, doi:http://dx.doi.org/10.1155/2012/415234. [18] F. Kanwal, R. Rehman, J. Anwar, T. Mahmud, Adsorption studies of cadmium (II) Using novel composites of polyaniline with rice husk and saw dust of Eucalyptus camaldulensis, Electron. J. Environ. Agric. Food Chem. 10 (2011) 2972– 2985. [19] P. Taylor, J. Wang, X. Han, Y. Ji, H. Ma, Desalination and water treatment adsorption of Cr(VI) from aqueous solution onto short-chain polyaniline/ palygorskite composites, Desalin. Water Treat. 37–41 (2014) , doi:http://dx. doi.org/10.1080/19443994.2014.935805. [20] S. Karthikaikumar, M. Karthikeyan, K.K.S. Kumar, Removal of Congo red dye from aqueous solution by polyaniline-montmorrillonite, Composites 2 (2014) 606–614. [21] F. Belaib, A.H. Meniai, M.B. Lehocine, Elimination of phenol by adsorption onto mineral/polyaniline composite solid support, Energ. Procedia 18 (2012) 1254– 1260, doi:http://dx.doi.org/10.1016/j.egypro.2012.05.141. [22] M.S. Öncel, Adsorption of copper(II) from aqueous solution by beidellite, Environ. Geol. 55 (8) (2008) 1767–1775, doi:http://dx.doi.org/10.1007/s00254007-1127-6. [23] M. Ghorbani, H. Eisazadeh, Removal of COD, color, anions and heavy metals from cotton textile wastewater by using polyaniline and polypyrrole nanocomposites coated on rice husk ash, Compos. B Eng. 45 (1) (2013) 1–7, doi: http://dx.doi.org/10.1016/j.compositesb.2012.09.035. [24] M. Ghorbani, H. Esfandian, N. Taghipour, R. Katal, Application of polyaniline and polypyrrole composites for paper mill wastewater treatment, Desalina-

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[25]

[26]

[27]

[28]

[29]

[30]

[31]

[32]

[33]

[34]

263 (1–3) (2010) 279–284, doi:http://dx.doi.org/10.1016/j. tion desal.2010.06.072. Z. Taghipour Kolaei, M. Tanzifi, A. Yousefi, H. Eisazadeh, Removal of Cd(II) from aqueous solution by using polyaniline/polystyrene nanocomposite, J. Vinyl Addit. Technol. 18 (1) (2012) 52–56, doi:http://dx.doi.org/10.1002/vnl.20279. P. Conte, A. Piccolo, High pressure size exclusion chromatography (HPSEC) of humic substances: molecular sizes, analytical parameters, and column performance, Chemosphere 38 (3) (1999) 517–528, doi:http://dx.doi.org/10.1016/ S0045-6535(98)00198-2. 10901671. B. Karagozoglu, M. Tasdemir, E. Demirbas, M. Kobya, The adsorption of basic dye (astrazon blue FGRL) from aqueous solutions onto sepiolite, fly ash and apricot shell activated carbon: kinetic and equilibrium studies, J. Hazard. Mater. 147 (1–2) (2007) 297–306, doi:http://dx.doi.org/10.1016/j.jhazmat.2007.01.003. 17270343. N. Kannan, M.M. Sundaram, Kinetics and mechanism of removal of methylene blue by adsorption on various carbons—a comparative study, Dyes Pigm. 51 (1) (2001) 25–40, doi:http://dx.doi.org/10.1016/S0143-7208(01)00056-0. Z. Rafiq, R. Nazir, M.R. Durr-E-Shahwar, S. Shah, Utilization of magnesium and zinc oxide nano-adsorbents as potential materials for treatment of copper electroplating industry wastewater, J. Environ. Chem. Eng. 2 (2014) 642–651, doi:http://dx.doi.org/10.1016/j.jece.2013.11.004. A.A. Khan, Inamuddin, Preparation, physico-chemical characterization, analytical applications and electrical conductivity measurement studies of an “organic–inorganic” composite cation-exchanger: polyaniline Sn(IV) phosphate, React. Funct. Polym. 66 (12) (2006) 1649–1663, doi:http://dx.doi.org/ 10.1016/j.reactfunctpolym.2006.06.007. R. Ansari, M. Banimahd Keivani, A. Fallah Delavar, Application of polyaniline nanolayer composite for removal of tartrazine dye from aqueous solutions, J. Polym. Res. 18 (6) (2011) 1931–1939, doi:http://dx.doi.org/10.1007/s10965011-9600-z. X. Jiang, Y. Rui, G. Chen, Improved properties of cotton by atmospheric pressure plasma polymerization deposition of sericin, J. Vinyl Addit. Technol. 20 (2009) 129–133, doi:http://dx.doi.org/10.1002/vnl. C. Guo, L. Zhou, J. Lv, Effects of expandable graphite and modified ammonium polyphosphate on the flame-retardant and mechanical properties of wood flour-polypropylene composites, Polym. Polym. Compos. 21 (2013) 449–456, doi:http://dx.doi.org/10.1002/app. E. Grundgeiger, Y.H. Lim, R.L. Frost, G.A. Ayoko, Y. Xi, Application of organobeidellites for the adsorption of atrazine, Appl. Clay Sci. 105–106 (2015) 252–258, doi:http://dx.doi.org/10.1016/j.clay.2015.01.003.

[35] H. Cui, Y. Qian, Q. Li, Q. Zhang, J. Zhai, Adsorption of aqueous Hg(II) by a polyaniline/attapulgite composite, Chem. Eng. J. 211–212 (2012) 216–223, doi: http://dx.doi.org/10.1016/j.cej.2012.09.057. [36] M.L. Occelli, Physicochemical properties of montmorillonite interlayered with cationic Oxyaluminum pillars, Clays Clay Miner. 31 (1) (1983) 22–28, doi: http://dx.doi.org/10.1346/CCMN.1983.0310104. [37] V. Janaki, K. Vijayaraghavan, B.-T. Oh, K.-J. Lee, K. Muthuchelian, A.K. Ramasamy, et al., Starch/polyaniline nanocomposite for enhanced removal of reactive dyes from synthetic effluent, Carbohydr. Polym. 90 (4) (2012) 1437–1444, doi:http://dx.doi.org/10.1016/j.carbpol.2012.07.012. 22944400. [38] E. Gengec, M. Kobya, Treatment of baker’s yeast wastewater by electrocoagulation and evaluation of molecular weight distribution with HPSEC, Sep. Sci. Technol. 48 (18) (2013) 2880–2889, doi:http://dx.doi.org/10.1080/ 01496395.2013.804087. [39] V. Janaki, B.-T. Oh, K. Shanthi, K.-J. Lee, A.K. Ramasamy, S. Kamala-Kannan, Polyaniline/chitosan composite: an eco-friendly polymer for enhanced removal of dyes from aqueous solution, Synth. Met. 162 (2012) 974–980, doi: http://dx.doi.org/10.1016/j.synthmet.2012.04.015. [40] E. Gengec, U. Ozdemir, B. Ozbay, I. Ozbay, S. Veli, Optimizing dye adsorption onto a waste-derived (modified charcoal ash) adsorbent using box-Behnken and central composite design procedures, Water Air Soil Pollut. 224 (10) (2013) 1751, doi:http://dx.doi.org/10.1007/s11270-013-1751-6. [41] S. Veli, B. Alyüz, Adsorption of copper and zinc from aqueous solutions by using natural clay, J. Hazard. Mater. 149 (1) (2007) 226–233, doi:http://dx.doi. org/10.1016/j.jhazmat.2007.04.109. 17560022. _ Özbay, U. Özdemir, B. Özbay, S. Veli, Kinetic, thermodynamic, and equilib[42] I. rium studies for adsorption of azo reactive dye onto a novel waste adsorbent: charcoal ash, Desalin. Water Treat. 51 (31–33) (2013) 6091–6100, doi:http:// dx.doi.org/10.1080/19443994.2013.763387. [43] Y. Zhang, Q. Li, L. Sun, R. Tang, J. Zhai, High efficient removal of mercury from aqueous solution by polyaniline / humic acid nanocomposite, J. Hazard. Mater. 175 (1–3) (2010) 404–409, doi:http://dx.doi.org/10.1016/j.jhazmat.2009.10.019. 19896766. [44] M. Ghorbani, H. Eisazadeh, Removal of COD, color, anions and heavy metals from cotton textile wastewater by using polyaniline and polypyrrole nanocomposites coated on rice husk ash, Compos. B Eng. 45 (1) (2013) 1–7, doi: http://dx.doi.org/10.1016/j.compositesb.2012.09.035.

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