An overview of zeolites synthesised from coal fly ash and their potential for extracting heavy metals from industrial wastewater

Zeolites are aluminosilicate minerals widely used in industrial applications including as commercial adsorbents and catalysts. This overview focuses on zeolites synthesised from coal fly ash (CFA). Human activities and industrial developments generate large volumes of polluted water, which have a significant ecological impact. Industrial wastewater may consist of different pollutant types, but of specific interest to this work are heavy metals, which. Heavy metal ions are among the most dangerous pollutants due to their toxicity and carcinogenicity. This overview covers the recent scientific literature, focused on using CFA-derived zeolites to remove Ni, Hg, Mn, Cu, Zn, Cd, Pb, Cr, Co both from synthetic solutions replicating industrial wastewater and actual wastewater streams. The results described in many papers cited in this review look promising for industrial wastewater treatment operations. Furthermore, the large variety of possible synthetic zeolites provides a route for energy-efficient, pollutant-specific remediation of industrial heavy metals

Magnetic Zeolite:Synthesis and Copper Adsorption Followed by Magnetic Separation from Treated Water

Zeolites are widely used in diverse applications, including the removal of heavy metals from wastewater. However, separating fine-sized zeolite particles from treated water is often a challenge. In this work, a novel method utilizing a colloidal polyvinyl alcohol (PVA) solution to bind iron oxide nanoparticles to a Linde Type A (LTA) zeolite was used to synthesize magnetic zeolite. Different zeolite–iron oxide nanoparticle loadings (10:1, 10:0.5, and 10:0.1) were used in batch adsorption experiments to investigate adsorption capacities and kinetics for Cu removal from an aqueous solution. The results showed that the magnetic zeolite maintained much of its adsorbent properties while facilitating a simplified process design. Thus, the adsorption capacity of pure LTA zeolite was found to be 262 mg/g for magnetic zeolite, with a 10:1 ratio—151 mg/g; 10:0.5—154 mg/g; and 10:0.1—170 mg/g. Magnetic separation was subsequently employed to remove the magnetic zeolite from the treated solution