Supplementary Materials
Supplementary Table 1: The element content of BEN from EDX analysis
Element / Composition (Wt. %)O / 63.48
Na / 2.81
Mg / 1.71
Al / 7.80
Si / 18.81
Cl / 1.54
Ca / 0.68
Fe / 3.18
Total / 100
Supplementary Table 2: Surface and pore characteristics of BEN and BEN-PVAG
Parameter / BEN / BEN-PVAGBET surface area, SBET (m2 g-1) / 49.72 / 12.12
Total pore volume, Vt (cm3 g-1) / 5.66 x 10-2 / 6.52 x 10-3
Average pore diameter, Davg (nm) / 5.29 / 4.09
Average particle size, Dps (nm) / 117 / 464
Supplementary Table 3: The Langmuir and Freundlich adsorption parameters of the BEN, suspended BEN-PVAG and immobilized BEN-PVAG/GP for MB
Model / Parameters / BEN / BEN-PVAG / BEN-PVAG/GPLangmuir isotherm / qmax (mg g-1) / 114.94 / 62.89 / 22.47
KL (L mg-1) / 2.18 / 0.05 / 0.04
R2 / 0.996 / 0.982 / 0.667
Freundlich isotherm / KF (mg g-1) / 48.60 / 11.43 / 1.138
n / 4.26 / 3.06 / 1.38
R2 / 0.766 / 0.998 / 0.980
Supplementary Table 4: Comparison of maximum monolayer adsorption capacities, qmax of different clay-based adsorbents for MB
Clay-based adsorbent / Adsorption capacity, qmax (mg g-1) / ReferencesNatural palygorskite / 48.39 / Chen et al. (2011)
700 °C treated palygorskite / 78.11 / Chen et al. (2011)
Al-pillared clay / 21 / Gil et al. (2011)
Zr-pillared clay / 27 / Gil et al. (2011)
Raw ball clay / 34.65 / Auta and Hameed (2012)
Modified ball clay / 100 / Auta and Hameed (2012)
Fe3O4-montmorillonite / 71.12 / Cottet et al. (2014)
Raw pyrophyllite / 3.71 / Zhang et al. (2015)
Pickled-ground pyrophyllite / 4.24 / Zhang et al. (2015)
BEN-PVAG (suspended) / 62.89 / This work
BEN-PVAG/GP (immobilized) / 22.47 / This work
Supplementary Fig. 1 Molecular structure of methylene blue (MB)
Supplementary Fig. 2 The experimental set-up for adsorption of MB solution by BEN-PVAG/GP consisted of (a) BEN-PVAG/GP, (b) custom made glass cell, (c) MB solution, (d) box, (e) aquarium pump, (f) iron stage, (g) flow meter, (h) poly (vinyl) chloride tubing and (i) Pasteur pipette.
Supplementary Fig. 3: Nitrogen adsorption and desorption isotherms of BEN and BEN-PVAG.
Supplementary Fig. 4: Point of zero charge, pHpzc of BEN and BEN-PVAG
Supplementary Fig. 5: XRD patterns of BEN, BEN-PVAG/GP, P-25TiO2 powder and P-25TiO2/BEN-PVAG/GP
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Supplementary Fig. 6: (a) UV-vis DRS of BEN-PVAG/GP, P-25TiO2/GP and P-25TiO2/BEN-PVAG/GP in absorbance modes and (b) Tauc plots for determination of band gap values for P-25TiO2/GP and P-25TiO2/BEN-PVAG/GP using Kubelka-Munk functio
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Supplementary Fig. 7: (a) Pseudo-first-order (b) pseudo-second-order and (c) Elovich kinetic plot for adsorption of MB onto BEN-PVAG/GP at different concentrations.
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Supplementary Fig. 8: Boyd kinetic plot for adsorption of MB onto (a) immobilized and (b) suspended BEN-PVAG at different concentrations
Supplementary Fig.9: Photocatalytic degradation of MB by P-25TiO2/BEN-PVAG with different ratio of BEN: PVAG (w/w).
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Supplementary Fig. 10: : (a) Effect of contact time on the adsorption of MB by the BEN-PVAG/GP and P-25TiO2/BEN-PVAG/GP; (b) comparison of MB degradation via photolysis, adsorption and photocatalysis by P-25TiO2/GP and P-25TiO2/BEN-PVAG/GP ([MB] = 10 mg L-1; pH 7; aeration rate = 100 mL min-1);