Valorization of an Electronic Waste-Derived Aluminosilicate: Surface Functionalization and Porous Structure Tuning

This study involves the sustainable development of an ion exchange material with ultrahigh heavy metal uptake capacity from a waste material, originally destined for landfills. In this study, a promising thermo-alkaline reaction has been employed to simultaneously alter the surface chemistry and tune the textural properties of the waste-derived aluminosilicate. The effects of several reaction variables on the formation of mesotunnels in the structure of the material have been examined. Also, the surface characterization of the functionalized aluminosilicate has demonstrated that the functionalization reaction results in the cleavage of the robust T-O-T' linkages (where T and T' = Si or Al) into T-O- moieties, counterbalanced by an alkali metal cation, resulting in the coverage of the aluminosilicate surface with active ion exchange sites. Comparison of the ion exchange capacity of the functionalized aluminosilicate with those of the commercial ion exchange resins has proven exceptionally higher heavy metal uptake for the former. The ultrahigh heavy metal uptake of this material is ascribed to the high concentration of developed counterbalancing cations on the material surface. The attractiveness of this innovative approach is manifested by the dual environmental benefit, i.e., sustainable upcycling of a waste formerly deposited in landfills and its utilization for heavy metal-laden wastewater treatment.