Magnetic multi-functional nano-fly ash-derived zeolite composites for environmental applications

Abstract

A new class of zeolites was synthesized featuring magnetic properties, and molecular sieve and high cation exchangeable capacity. The magnetic properties enable the effective separation of the spent composites from complex multiphase systems for regeneration and recycling, safe waste disposal and the recovery of loaded valuable species. The zeolite provides the matrix for supporting an incredible new, simple, efficient and economical method to synthesize stable, nano-scale zero-valent iron (NZVI)-modified zeolites by hydrothermal reaction. The NZVI has excellent properties such as high reactivity and good thermal stability without aggregation. Thus, iron can be impregnated into the framework of the zeolite and act as components providing the desired functionality in a wide range of applications. The magnetic component (Fe⁰), zeolite matrix and iron impregnated into the framework of the zeolite together form the unique novel composite with designed functions. It represents a practically operational, economically sustainable and environmentally friendly new advanced functional material. The paper focuses on the novel synthesis and characterization of the composite and shows an example of its application as a sorbent for the removal of ammonium from water. The multi-functional materials have potential applications as recyclable catalysts, the filler of bioreactors, and sorbents.