Enhanced Performance of Hydrogen Peroxide Modified Pozzolan-Based Geopolymer for Abatement of Methylene Blue from Aqueous Medium

Abstract

Pozzolan-based eco-adsorbents were synthesized by geopolymerization with addition of hydrogen peroxide (H2O2) with mass ratios 0% (GP0) and 1% (GP1) and the products used to sorb cationic methylene blue (MB) dye from water. The chemical composition, textural properties, mineral composition, surface functions, as well as morphology and internal structure of these samples were determined by the X-ray fluorescence, adsorption of nitrogen by the B.E.T (Bruamer Emmet Teller) method, X-ray diffraction, Fourier Transformed Infrared Spectroscopy (FTIR) and scanning electron microscopy (SEM), respectively. The effects of contact time, dye initial concentration, adsorbent dosage, pH and temperature were examined and are herein reported. Incorporation of 1% H2O2 increased the specific surface area from 4.344 to 5.610 m 2 /g representing ~29% increase in surface area. This translated an increase in the MB adsorption capacity by 15 orders of magnitude from 24.4 to 366.2 mg/g for GP0 and GP1, respectively. The adsorption rates of methylene blue on the two geopolymers were best described by the pseudo-second order kinetic model. The adsorption equilibrium data were best described by the Sips and Freundlich isotherms models for GP0 and GP1, respectively.Thermodynamically, it was determined that the adsorption of methylene blue onto GP0 and GP1 is a physical and endothermic process. The results show that incorporation of low amount of hydrogen peroxide into pozzolan-based geopolymers increases their adsorption capacity for methylene blue dye stupendously while preserving the surface chemistry.

Removal of endosulfan from water by municipal waste incineration fly ash-based geopolymers: Adsorption kinetics, isotherms, and thermodynamics

“…Values comparable to those in this study and similar findings have been reported by Sarkar et al (2019) and Hermann et al (2022).…”

“…The point of zero charge is the pH at which the net charge on the adsorbent surface is zero. The pH point of the zero charge of MWFA and the synthesized geopolymers (pH pzc ) was determined using the pH drift method (Dzoujo et al, 2022;Hermann et al, 2022).…”

“…C e is the equilibrium endosulfan concentration in the solution (mg/L), and C ads represents the equilibrium endosulfan concentration in the solid phase (mg/g). K d is the distribution coefficient (L/g), and the density of water is 1,000 g/ L (Hermann et al, 2022).…”

Porous alkali‐activated material from hypergolic coal gangue by microwave foaming for methylene blue removal

“…117,118 The second is related to n-π interactions between the structure of PAAMs and the MB-conjugated structure. 117,118 A third aspect takes into account the electrostatic interactions between the positively charged sites of MB + and the negatively charged tetrahedral Al sites. 86,105 Finally, hydroxyl groups (−OH) attract the N or S atoms of the MB dye to form hydrogen bonds.…”

“…The first aspect is the ion exchange properties of MB cations and Na + charge-balancing cations in the PAAM network. 117,118 The second is related to n-π interactions between the structure of PAAMs and the MB-conjugated structure. 117,118 A third aspect takes into account the electrostatic interactions between the positively charged sites of MB + and the negatively charged tetrahedral Al sites.…”