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A facile method for preparation of floatable and permeable fly ash-based geopolymer block
Materials Letters 185 (2016) 370–373
Contents lists available at ScienceDirect
Materials Letters journal homepage: www.elsevier.com/locate/matlet
A facile method for preparation of floatable and permeable fly ash-based geopolymer block
crossmark
⁎
Yi Liua,b,c, Chunjie Yana,b, , Zuhua Zhangc,⁎⁎, Yansheng Gonga, Hongquan Wanga,b, Xiumei Qiud a
Faculty of Material science and Chemistry, China University of Geosciences, Wuhan 430074, China Engineering Research Center of Nano-Geomaterials of Education Ministry, China University of Geosciences, Wuhan 430074, China Centre for Future Materials, University of Southern Queensland, Toowoomba 4350, QLD, Australia d Hubei province geological experimental testing center, Wuhan 430034, China b c
A R T I C L E I N F O
A BS T RAC T
Keywords: Geopolymer foams Open cell Floatable Adsorbent Fly ash
We present a process of fabricating water floatable and permeable geopolymer block from industrial by-product fly ash. By adding oleic acid and H2O2 solution during the geopolymer manufacture process, a foamed geopolymer block with highly interconnected pores can be manufactured. The compressive strength of those foamed geopolymer block are 0.55 ± 0.08 MPa at dry density of 0.37 g/cm3, and its permeability to water coefficient is 0.35 cm/s and the BET surface area is 67.62 m2/g. In addition, the porous geopolymer block possesses a high adsorption capacity for methylene blue, 50.7 ± 0.7 mg/g, and shows the potential of being employed as low cost replacement for zeolites in applications such as waste water treatment at high mass transport rate.
1. Introduction
2. Materials and methods
Geopolymers are a class of alkali-activated aluminosilicate materials and they have been developed very quickly in the last two decades [1]. Geopolymers have almost the same structure at atomic scale with zeolite, and are considered to be the precursor of zeolites. They have gained significant interests in waste treatment applications. Moreover, geopolymers have been proven to be effective in absorption of heavy metals [2–5] and dyes [6]. In comparison with zeolite synthesis, geopolymer technology can avoid the problems such as alkaline pollution, low yields and high costs during the manufacturing process. Geopolymer block with dense structure limits the permeability to liquids, thus geopolymer block with interconnected pores will be favorable in the absorption process. Plenty of efforts have been done to produce geopolymer foams [7–10]; however most of the geopolymer produced by using common methods were closed cell foamed geopolymer. This is due to the fact that the density of geopolymer reaches a level that allows the binder to isolate individual air bubbles, and most voids formed in geopolymer are therefore closed. In this study the authors have made an innovative approach to design geopolymer with floating and permeable properties. The floating and adsorptive characters of geopolymer have great potential in waste treatment applications.
Circulating fluidized bed fly ash, obtained from Shenhua Junggar Energy Corporation in Junggar, Inner Mongolia, China, was used as raw material. The chemical compositions of fly ash were determined by X-ray fluorescence (AXIOSmAX, PANalytical Netherlands). Analytical grade sodium hydroxide, H2O2 solution (30%) and methylene blue trihydrate were supplied by Sinopharm Chemical Reagent Co., Ltd. Analytical grade oleic acid was supplied by Tianjin Fuchen Chemical Reagents Factory. Commercial sodium water glass was obtained from Shenghuai Chemical Technology Co. Ltd., Foshan, with original modulus of 3.25. The process of geopolymer foam synthesis is shown in Fig. 1. The first step was the preparation of alkaline activator, as reported in a previous article [11]. The alkaline activator was thoroughly mixed by a high-speed dispersion machine (U400/80-220, Shanghai Mihai industry Co., Ltd) at 2000 rpm for 10 min. Then fly ash was added to the activator solution (activator/ash ratio=0.97), stirring at 1200 rpm for 5–8 min to make the homogeneous geopolymer paste. Oleic acid (7.0 wt% on the weight of fly ash) was then added to the geopolymer paste and mixed for another 3–5 min. After that H2O2 solution was added to the geopolymer paste at the ratio of 4.5 wt% with respect to the weight of fly ash, stirring at 1500 rpm for 3–5 min to make geopolymer foam. Finally the geopolymer foam was cast into a silicone
⁎
Corresponding author at: Faculty of Material science and Chemistry, China University of Geosciences, Wuhan 430074, China. Corresponding author. E-mail addresses: [email protected] (C. Yan), [email protected] (Z. Zhang).
⁎⁎
http://dx.doi.org/10.1016/j.matlet.2016.09.044 Received 4 July 2016; Received in revised form 5 September 2016; Accepted 11 September 2016 Available online 12 September 2016 0167-577X/ © 2016 Elsevier B.V. All rights reserved.
Materials Letters 185 (2016) 370–373
Y. Liu et al.
Fig. 1. The fabrication of floatable and permeable fly ash-based geopolymer block.
for 48 h. The MB concentrations were analyzed by a spectrophotometer (723, Shanghai Jinghua Technology Instrument Co., Ltd) at λmax of 665 nm.
rubber mold (33 mm×33 mm×33 mm) and sealed with a plastic bag and cured at 80 °C for 10 h into an oven, the foamed geopolymer was named as GEOO for short. For comparison, samples without oleic acid and H2O2 solution (GEO), with H2O2 solution but without oleic acid (GEOH) were also produced. Prior to the characterization, the geopolymer was washed using hot water for several times until the water remains clear, which means almost complete extraction of oleate which is generated by the neutralization reaction between oleic acid and alkaline geopolymer paste. The morphologies of all the fracture surfaces of geopolymer samples were analyzed using a scanning electron microscopy (SU8010, Hitachi Japan). The FTIR spectra of the samples were obtained using Nicolet iS50 spectrometer (Thermo Scientific America). Nitrogen gas adsorption–desorption experiments were performed at 77 K using an automatic ASAP2020 surface area and porosimetry system (Micromeritics, America), and the specific surface area was calculated by the Brunauer–Emmet–Teller (BET) method. The pore size distributions were obtained from the N2 adsorption branch of nitrogen isotherms by using the Barrett-Joyner-Halenda (BJH) model. The compressive strength was tested by a Universal Material Testing Machine (NKK-4050, made in Shenzhen, China), with a moving velocity of 1.0 mm/min of the loader. Laboratory based permeability tests were done to test the permeability coefficient (K, cm/s) of GEOO sample. The method is in accordance with Li et al. [12]. The test is based on the Darcy's law, which can be written as Eq. (1):
K=
QL △Φ S
3. Results and discussion The chemical composition of fly ash is shown in Table 1. It has high contents of Al2O3 and SiO2. Geopolymer pastes were formulated initially at target molar ratios of SiO2/Al2O3=2.0, Na2O/SiO2=0.32 and H2O/Na2O=9.0. At this ratio the mixtures show favorable workability. Fig. 2a shows the as received fly ash is granulated particles with irregular shape and different particle sizes. After being activated with alkaline activator, fly ash granules reached a high extent of reaction, as illustrated in Fig. 2b. Fig. 2c demonstrates the GEOH sample has closed pores. The foaming agent of H2O2 solution has an uncontrollable foaming rate, thus, the GEOH sample has heterogeneous pores. The results are in agreement with literatures [13,14]. From Fig. 2d, it is able to observe geopolymer with adding oleic acid and H2O2 solution possessing highly interconnected pores. The cell walls of the pores have irregular openings interconnecting the adjacent pores, which enables high water permeability (as illustrated in Fig. 1). The permeability coefficient of open cell geopolymer is determined to be 0.35 cm/s. The structural characteristics of GEO and GEOO were investigated by FTIR analyses (Fig. 3a). In comparison, the FTIR spectrum of GEOO shows new weak bands at 2926 and 2856 cm−1, which are attributed to the asymmetric and symmetric stretch of -CH2-, due to the oleic acid chains. For the GEO sample, the bands around 1452 cm−1 is attributed to O–C–O stretching vibration. While in the spectrum of GEOO sample, it disappears. Instead, there are two weak bands at 1545 and 1453 cm−1, which are attribute to the asymmetric and symmetric stretching frequencies of carboxyl groups. It is assumed that part of oleate molecules have coated on the foamed geopolymer. The oleate molecules play a role as hydrophobic modifier, and the hydrophobic modification results in the open cell geopolymer block float in water.
(1)
where Q (ml/s) is the flow rate, L (cm) is the length of flow path, △Φ (cm) is the hydraulic potential difference, S (cm2) is the cross-sectional area perpendicular to flow direction. We investigated the efficiency of GEOO as absorbents for methylene blue (MB) from aqueous solution. The sample was grinded and pass through a 100 mesh sieve. Different dosage of GEOO sample was added to vials to contact with 100 ml MB solution, shaken at 150 rpm at 25 °C 371
Materials Letters 185 (2016) 370–373
Y. Liu et al.
Table 1 Chemical composition of fly ash by XRF analysis (wt%). Sample
Al2O3
SiO2
Fe2O3
TiO2
K2O
Na2O
CaO
MgO
P2O5
MnO
LOI
FA
52.2
38.3
1.9
2.2
0.4
< 0.1
1.1
< 0.1
0.2
< 0.1
3.3
LOI=loss on ignition.
Fig. 2. Morphology of (a) raw fly ash; (b) geopolymer; (c) geopolymer with H2O2 solution; (d) geopolymer with oleic acid and H2O2 solution.
Fig. 3. Infrared analysis (a), BJH pore size distribution (b) and adsorption capacity (c) of open cell geopolymer foams.
is at sizes about 10 nm. The extraction of oleate creates micro-, mesoand macro- pores, meanwhile, increases the specific surface area of the foamed geopolymer. Fig. 3c presents the MB adsorption capacity and removal efficiency. The removal efficiency increase with the increase of GEOO adsorbent. When the dosage is over 0.4 g, the removal efficiency keeps almost constant at about 98%. The amount of MB adsorbed on the adsorbent decreases with the increase of GEOO when the dosage is over 0.4 g for the lack of MB in the solution. Thus, based on the adsorption amount
The compression strength of the open cell foamed geopolymers are 0.55 ± 0.08 MPa, which are a little lower than the closed cell foamed geopolymers (between 1 and 10 MPa) [8]. The GEOO sample was smashed and screened through mesh size of 200 to test its surface area and small pore volume. The BET surface area of GEOO sample is up to 67.62 m2/g, even higher than some porous zeolite spheres [15]. The BJH pore volume is 0.16 cm3/g. The pore size distributions of GEOO sample is given in Fig. 3b. As shown that the dominant pores in nanoscale of the open cell geopolymer foam 372
Materials Letters 185 (2016) 370–373
Y. Liu et al.
supported by Australian (LP130101016).
we can obtain the adsorption capacity of MB on GEOO (50.7 ± 0.7 mg/ g) within 48 h, which is comparable to the zeolites synthesized from fly ash [16].
Research
Council
linkage
project
References 4. Conclusions [1] Z. Zhang, J.L. Provis, J. Zou, A. Reid, H. Wang, Cem. Concr. Res 85 (2016) 163–173. [2] S. Wang, L. Li, Z.H. Zhu, J. Hazard. Mater. 139 (2) (2007) 254–259. [3] Y. Ge, X. Cui, Y. Kong, Z. Li, Y. He, Q. Zhou, J. Hazard. Mater. 283 (2015) 244–251. [4] K. Al-Zboon, M.S. Al-Harahsheh, F.B. Hani, J. Hazard. Mater. 188 (1–3) (2011) 414–421. [5] Y. Liu, C. Yan, Z. Zhang, H. Wang, S. Zhou, W. Zhou, Fuel 185 (2016) 181–189. [6] L. Li, S. Wang, Z. Zhu, J. Colloid Interface Sci. 300 (1) (2006) 52–59. [7] M. Lassinantti Gualtieri, M. Romagnoli, A.F. Gualtieri, J. Eur. Ceram. Soc. 35 (11) (2015) 3167–3178. [8] Z. Zhang, J.L. Provis, A. Reid, H. Wang, Constr. Build Mater. 56 (2014) 113–127. [9] M.M. Al. Bakri Abdullah, K. Hussin, M. Bnhussain, K.N. Ismail, Z. Yahya, R. A. Razak, Int. J. Mol. Sci. 13 (6) (2012) 7186–7198. [10] E. Prud’homme, P. Michaud, E. Joussein, C. Peyratout, A. Smith, S. Arrii-Clacens, J.M. Clacens, S. Rossignol, J. Eur. Ceram. Soc. 30 (7) (2010) 1641–1648. [11] Y. Liu, C. Yan, X. Qiu, D. Li, H. Wang, A. Alshameri, J. Taiwan Inst. Chem. Eng. 59 (2016) 433–439. [12] X. Li, Q. Xu, S. Chen, Constr. Build. Mater. 105 (2016) 503–510. [13] Z. Zhang, L. Li, D. He, X. Ma, C. Yan, H. Wang, Mater. Lett. 178 (2016) 151–154. [14] G. Masi, W.D.A. Rickard, L. Vickers, M.C. Bignozzi, A. van Riessen, Ceram. Int 40 (9) (2014) 13891–13902. [15] Q. Tang, Y.-y Ge, K.-t Wang, Y. He, X.-m Cui, Mater. Lett. 161 (2015) 558–560. [16] C.F. Wang, J.S. Li, L.J. Wang, X.Y. Sun, J.J. Huang, Chin. J. Chem. Eng. 17 (3) (2009) 513–521.
A facile method for preparation of floatable and highly permeable fly ash-based geopolymer block is reported for the first time. Taking H2O2 solution as a blowing agent will make a closed cell geopolymer foam, and with the addition of oleic acid the geopolymer foam will possess highly interconnected pores. The in situ formation of oleate molecules enabled the creation of openings on the cell walls and avoid the interconnected wet pores from collapse. In short, the fly ash-based foamed geopolymer is inexpensive, convenient and a ready for use material to remove dyes from wastewater. The floatable property of the geopolymer foam make it easy to be recycled after the treatment for waste water, the interconnected pores with high permeability ensure a large contact area with water, and the proven adsorption capacity to MB suggest its high potential in waste water treatment. Acknowledgment This work was supported by the Public Service Project of the Chinese Ministry of Land and Resources (No. 201311024) and China Scholarship Council (No. 201606410038). The participation of Z.Z. is
373
Contents lists available at ScienceDirect
Materials Letters journal homepage: www.elsevier.com/locate/matlet
A facile method for preparation of floatable and permeable fly ash-based geopolymer block
crossmark
⁎
Yi Liua,b,c, Chunjie Yana,b, , Zuhua Zhangc,⁎⁎, Yansheng Gonga, Hongquan Wanga,b, Xiumei Qiud a
Faculty of Material science and Chemistry, China University of Geosciences, Wuhan 430074, China Engineering Research Center of Nano-Geomaterials of Education Ministry, China University of Geosciences, Wuhan 430074, China Centre for Future Materials, University of Southern Queensland, Toowoomba 4350, QLD, Australia d Hubei province geological experimental testing center, Wuhan 430034, China b c
A R T I C L E I N F O
A BS T RAC T
Keywords: Geopolymer foams Open cell Floatable Adsorbent Fly ash
We present a process of fabricating water floatable and permeable geopolymer block from industrial by-product fly ash. By adding oleic acid and H2O2 solution during the geopolymer manufacture process, a foamed geopolymer block with highly interconnected pores can be manufactured. The compressive strength of those foamed geopolymer block are 0.55 ± 0.08 MPa at dry density of 0.37 g/cm3, and its permeability to water coefficient is 0.35 cm/s and the BET surface area is 67.62 m2/g. In addition, the porous geopolymer block possesses a high adsorption capacity for methylene blue, 50.7 ± 0.7 mg/g, and shows the potential of being employed as low cost replacement for zeolites in applications such as waste water treatment at high mass transport rate.
1. Introduction
2. Materials and methods
Geopolymers are a class of alkali-activated aluminosilicate materials and they have been developed very quickly in the last two decades [1]. Geopolymers have almost the same structure at atomic scale with zeolite, and are considered to be the precursor of zeolites. They have gained significant interests in waste treatment applications. Moreover, geopolymers have been proven to be effective in absorption of heavy metals [2–5] and dyes [6]. In comparison with zeolite synthesis, geopolymer technology can avoid the problems such as alkaline pollution, low yields and high costs during the manufacturing process. Geopolymer block with dense structure limits the permeability to liquids, thus geopolymer block with interconnected pores will be favorable in the absorption process. Plenty of efforts have been done to produce geopolymer foams [7–10]; however most of the geopolymer produced by using common methods were closed cell foamed geopolymer. This is due to the fact that the density of geopolymer reaches a level that allows the binder to isolate individual air bubbles, and most voids formed in geopolymer are therefore closed. In this study the authors have made an innovative approach to design geopolymer with floating and permeable properties. The floating and adsorptive characters of geopolymer have great potential in waste treatment applications.
Circulating fluidized bed fly ash, obtained from Shenhua Junggar Energy Corporation in Junggar, Inner Mongolia, China, was used as raw material. The chemical compositions of fly ash were determined by X-ray fluorescence (AXIOSmAX, PANalytical Netherlands). Analytical grade sodium hydroxide, H2O2 solution (30%) and methylene blue trihydrate were supplied by Sinopharm Chemical Reagent Co., Ltd. Analytical grade oleic acid was supplied by Tianjin Fuchen Chemical Reagents Factory. Commercial sodium water glass was obtained from Shenghuai Chemical Technology Co. Ltd., Foshan, with original modulus of 3.25. The process of geopolymer foam synthesis is shown in Fig. 1. The first step was the preparation of alkaline activator, as reported in a previous article [11]. The alkaline activator was thoroughly mixed by a high-speed dispersion machine (U400/80-220, Shanghai Mihai industry Co., Ltd) at 2000 rpm for 10 min. Then fly ash was added to the activator solution (activator/ash ratio=0.97), stirring at 1200 rpm for 5–8 min to make the homogeneous geopolymer paste. Oleic acid (7.0 wt% on the weight of fly ash) was then added to the geopolymer paste and mixed for another 3–5 min. After that H2O2 solution was added to the geopolymer paste at the ratio of 4.5 wt% with respect to the weight of fly ash, stirring at 1500 rpm for 3–5 min to make geopolymer foam. Finally the geopolymer foam was cast into a silicone
⁎
Corresponding author at: Faculty of Material science and Chemistry, China University of Geosciences, Wuhan 430074, China. Corresponding author. E-mail addresses: [email protected] (C. Yan), [email protected] (Z. Zhang).
⁎⁎
http://dx.doi.org/10.1016/j.matlet.2016.09.044 Received 4 July 2016; Received in revised form 5 September 2016; Accepted 11 September 2016 Available online 12 September 2016 0167-577X/ © 2016 Elsevier B.V. All rights reserved.
Materials Letters 185 (2016) 370–373
Y. Liu et al.
Fig. 1. The fabrication of floatable and permeable fly ash-based geopolymer block.
for 48 h. The MB concentrations were analyzed by a spectrophotometer (723, Shanghai Jinghua Technology Instrument Co., Ltd) at λmax of 665 nm.
rubber mold (33 mm×33 mm×33 mm) and sealed with a plastic bag and cured at 80 °C for 10 h into an oven, the foamed geopolymer was named as GEOO for short. For comparison, samples without oleic acid and H2O2 solution (GEO), with H2O2 solution but without oleic acid (GEOH) were also produced. Prior to the characterization, the geopolymer was washed using hot water for several times until the water remains clear, which means almost complete extraction of oleate which is generated by the neutralization reaction between oleic acid and alkaline geopolymer paste. The morphologies of all the fracture surfaces of geopolymer samples were analyzed using a scanning electron microscopy (SU8010, Hitachi Japan). The FTIR spectra of the samples were obtained using Nicolet iS50 spectrometer (Thermo Scientific America). Nitrogen gas adsorption–desorption experiments were performed at 77 K using an automatic ASAP2020 surface area and porosimetry system (Micromeritics, America), and the specific surface area was calculated by the Brunauer–Emmet–Teller (BET) method. The pore size distributions were obtained from the N2 adsorption branch of nitrogen isotherms by using the Barrett-Joyner-Halenda (BJH) model. The compressive strength was tested by a Universal Material Testing Machine (NKK-4050, made in Shenzhen, China), with a moving velocity of 1.0 mm/min of the loader. Laboratory based permeability tests were done to test the permeability coefficient (K, cm/s) of GEOO sample. The method is in accordance with Li et al. [12]. The test is based on the Darcy's law, which can be written as Eq. (1):
K=
QL △Φ S
3. Results and discussion The chemical composition of fly ash is shown in Table 1. It has high contents of Al2O3 and SiO2. Geopolymer pastes were formulated initially at target molar ratios of SiO2/Al2O3=2.0, Na2O/SiO2=0.32 and H2O/Na2O=9.0. At this ratio the mixtures show favorable workability. Fig. 2a shows the as received fly ash is granulated particles with irregular shape and different particle sizes. After being activated with alkaline activator, fly ash granules reached a high extent of reaction, as illustrated in Fig. 2b. Fig. 2c demonstrates the GEOH sample has closed pores. The foaming agent of H2O2 solution has an uncontrollable foaming rate, thus, the GEOH sample has heterogeneous pores. The results are in agreement with literatures [13,14]. From Fig. 2d, it is able to observe geopolymer with adding oleic acid and H2O2 solution possessing highly interconnected pores. The cell walls of the pores have irregular openings interconnecting the adjacent pores, which enables high water permeability (as illustrated in Fig. 1). The permeability coefficient of open cell geopolymer is determined to be 0.35 cm/s. The structural characteristics of GEO and GEOO were investigated by FTIR analyses (Fig. 3a). In comparison, the FTIR spectrum of GEOO shows new weak bands at 2926 and 2856 cm−1, which are attributed to the asymmetric and symmetric stretch of -CH2-, due to the oleic acid chains. For the GEO sample, the bands around 1452 cm−1 is attributed to O–C–O stretching vibration. While in the spectrum of GEOO sample, it disappears. Instead, there are two weak bands at 1545 and 1453 cm−1, which are attribute to the asymmetric and symmetric stretching frequencies of carboxyl groups. It is assumed that part of oleate molecules have coated on the foamed geopolymer. The oleate molecules play a role as hydrophobic modifier, and the hydrophobic modification results in the open cell geopolymer block float in water.
(1)
where Q (ml/s) is the flow rate, L (cm) is the length of flow path, △Φ (cm) is the hydraulic potential difference, S (cm2) is the cross-sectional area perpendicular to flow direction. We investigated the efficiency of GEOO as absorbents for methylene blue (MB) from aqueous solution. The sample was grinded and pass through a 100 mesh sieve. Different dosage of GEOO sample was added to vials to contact with 100 ml MB solution, shaken at 150 rpm at 25 °C 371
Materials Letters 185 (2016) 370–373
Y. Liu et al.
Table 1 Chemical composition of fly ash by XRF analysis (wt%). Sample
Al2O3
SiO2
Fe2O3
TiO2
K2O
Na2O
CaO
MgO
P2O5
MnO
LOI
FA
52.2
38.3
1.9
2.2
0.4
< 0.1
1.1
< 0.1
0.2
< 0.1
3.3
LOI=loss on ignition.
Fig. 2. Morphology of (a) raw fly ash; (b) geopolymer; (c) geopolymer with H2O2 solution; (d) geopolymer with oleic acid and H2O2 solution.
Fig. 3. Infrared analysis (a), BJH pore size distribution (b) and adsorption capacity (c) of open cell geopolymer foams.
is at sizes about 10 nm. The extraction of oleate creates micro-, mesoand macro- pores, meanwhile, increases the specific surface area of the foamed geopolymer. Fig. 3c presents the MB adsorption capacity and removal efficiency. The removal efficiency increase with the increase of GEOO adsorbent. When the dosage is over 0.4 g, the removal efficiency keeps almost constant at about 98%. The amount of MB adsorbed on the adsorbent decreases with the increase of GEOO when the dosage is over 0.4 g for the lack of MB in the solution. Thus, based on the adsorption amount
The compression strength of the open cell foamed geopolymers are 0.55 ± 0.08 MPa, which are a little lower than the closed cell foamed geopolymers (between 1 and 10 MPa) [8]. The GEOO sample was smashed and screened through mesh size of 200 to test its surface area and small pore volume. The BET surface area of GEOO sample is up to 67.62 m2/g, even higher than some porous zeolite spheres [15]. The BJH pore volume is 0.16 cm3/g. The pore size distributions of GEOO sample is given in Fig. 3b. As shown that the dominant pores in nanoscale of the open cell geopolymer foam 372
Materials Letters 185 (2016) 370–373
Y. Liu et al.
supported by Australian (LP130101016).
we can obtain the adsorption capacity of MB on GEOO (50.7 ± 0.7 mg/ g) within 48 h, which is comparable to the zeolites synthesized from fly ash [16].
Research
Council
linkage
project
References 4. Conclusions [1] Z. Zhang, J.L. Provis, J. Zou, A. Reid, H. Wang, Cem. Concr. Res 85 (2016) 163–173. [2] S. Wang, L. Li, Z.H. Zhu, J. Hazard. Mater. 139 (2) (2007) 254–259. [3] Y. Ge, X. Cui, Y. Kong, Z. Li, Y. He, Q. Zhou, J. Hazard. Mater. 283 (2015) 244–251. [4] K. Al-Zboon, M.S. Al-Harahsheh, F.B. Hani, J. Hazard. Mater. 188 (1–3) (2011) 414–421. [5] Y. Liu, C. Yan, Z. Zhang, H. Wang, S. Zhou, W. Zhou, Fuel 185 (2016) 181–189. [6] L. Li, S. Wang, Z. Zhu, J. Colloid Interface Sci. 300 (1) (2006) 52–59. [7] M. Lassinantti Gualtieri, M. Romagnoli, A.F. Gualtieri, J. Eur. Ceram. Soc. 35 (11) (2015) 3167–3178. [8] Z. Zhang, J.L. Provis, A. Reid, H. Wang, Constr. Build Mater. 56 (2014) 113–127. [9] M.M. Al. Bakri Abdullah, K. Hussin, M. Bnhussain, K.N. Ismail, Z. Yahya, R. A. Razak, Int. J. Mol. Sci. 13 (6) (2012) 7186–7198. [10] E. Prud’homme, P. Michaud, E. Joussein, C. Peyratout, A. Smith, S. Arrii-Clacens, J.M. Clacens, S. Rossignol, J. Eur. Ceram. Soc. 30 (7) (2010) 1641–1648. [11] Y. Liu, C. Yan, X. Qiu, D. Li, H. Wang, A. Alshameri, J. Taiwan Inst. Chem. Eng. 59 (2016) 433–439. [12] X. Li, Q. Xu, S. Chen, Constr. Build. Mater. 105 (2016) 503–510. [13] Z. Zhang, L. Li, D. He, X. Ma, C. Yan, H. Wang, Mater. Lett. 178 (2016) 151–154. [14] G. Masi, W.D.A. Rickard, L. Vickers, M.C. Bignozzi, A. van Riessen, Ceram. Int 40 (9) (2014) 13891–13902. [15] Q. Tang, Y.-y Ge, K.-t Wang, Y. He, X.-m Cui, Mater. Lett. 161 (2015) 558–560. [16] C.F. Wang, J.S. Li, L.J. Wang, X.Y. Sun, J.J. Huang, Chin. J. Chem. Eng. 17 (3) (2009) 513–521.
A facile method for preparation of floatable and highly permeable fly ash-based geopolymer block is reported for the first time. Taking H2O2 solution as a blowing agent will make a closed cell geopolymer foam, and with the addition of oleic acid the geopolymer foam will possess highly interconnected pores. The in situ formation of oleate molecules enabled the creation of openings on the cell walls and avoid the interconnected wet pores from collapse. In short, the fly ash-based foamed geopolymer is inexpensive, convenient and a ready for use material to remove dyes from wastewater. The floatable property of the geopolymer foam make it easy to be recycled after the treatment for waste water, the interconnected pores with high permeability ensure a large contact area with water, and the proven adsorption capacity to MB suggest its high potential in waste water treatment. Acknowledgment This work was supported by the Public Service Project of the Chinese Ministry of Land and Resources (No. 201311024) and China Scholarship Council (No. 201606410038). The participation of Z.Z. is
373