Adsorption is an effective method for removing heavy metals from water. Herein, a geopolymer synthesized from biomass fly ash was tested as an adsorbent for removing Pb from solution. The effects of contact time, pH, adsorbent dosage, and initial Pb concentration were tested. The results showed that this is a viable option for removing Pb from solution and reducing the accumulation of biomass fly ash.

Abstract

The effectiveness of low-cost fly ash geopolymer (FAGP) adsorbents synthesized from biomass fly ash in lead removal from aqueous solution was studied. The synthesized FAGP was characterized by the Brunauer-Emmett-Teller method and energy dispersive spectroscopy. The adsorption experiments were performed in batch mode under various conditions, and the maximum removal efficiency and uptake were found at an optimum time of 120 min and pH 5. Adsorption isotherm studies confirmed that lead removal is best fitted by both Langmuir and Freundlich isotherms. A kinetic analysis showed that pseudo-second-order kinetics governs lead adsorption. Lead adsorption was determined to be an endothermic, spontaneous process through thermodynamic analysis.