Synergistic effects of iron (Fe) and biochar on light-weight geopolymers when used in wastewater treatment applications

Abstract The conventional geopolymer usually has bad wastewater treatment ability. How to maximum improve the wastewater treatment ability of geopolymer become a hot topic. The synergistic effects of iron (Fe) and biochar on the circulation fluidized bed combustion fly-ash and bottom ash-based geopolymer (BFBAG) in the removal of dyes and toxic heavy metals were investigated. The hydration numerical models of BFBAG and immobilization mechanisms of heavy metals were proposed at first time. The removal efficiency (RE) of geopolymer with and without Fe is 68% and 84%, respectively, and the RE difference of geopolymer with Fe and biochar is 87%. It indicated that Fe and Biochar had synergistic catalytic effects when used in geopolymer for wastewater treatment applications. During the geopolymer production/formation process, whilst Fe enhanced the removal efficiency of the methylene blue dye, Biochar was concurrently instrumental in enhancing the immobilization efficiency and removal of the toxic heavy metals from the wastewater.