Iron-zirconium microwave-assisted modification of small-pore zeolite W and its alginate composites for enhanced aqueous removal of As(V) ions: experimental and theoretical studies

Abstract The requirement for enhanced, low-cost, and eco-friendly materials are highly favored for water treatment processes. Then, for extended application prospects, a simple and cost-effective method for composites preparation is mainly investigated. In the present work, a rapid and efficient modification of fly ash-based zeolite W (ZW) was achieved using a microwave-assisted process and then was applied to remove arsenate (As(V)) from water. The exchange equilibrium was reached after 1 min at 150 °C under microwave heating, where the iron and zirconium contents were 6.9 and 5.04 wt.%, respectively. The modified zeolite (FeZrZW) demonstrated an excellent efficiency toward As(V) ions up to 99.87% across a broad pH, from acidic 2 to basic 10. A high adsorption capacity of As(V) was obtained (Qm= 42.31 mg g-1) than all natural or fly ash-based zeolites, much higher than some commercial and synthetic adsorbents. The high arsenate uptake performance of FeZrZW adsorbent could be related to the creation of active acid sites on ZW after its modification containing iron and zirconium oxides, which capture through the formation of Zr-O-As and Fe-O-As bridges. Monte Carlo simulation results confirmed the stronger and spontaneous adsorption onto FeZrZW and gave more insights into the interaction between arsenic species and the adsorbents. In addition, alginate@FeZrZW composites were suggested as an alternative solution to the separation problem of arsenate in solution. They proved a remarkable efficiency up to 99.87% and an adsorption capacity of 29.38 mg g-1. Finally, FeZrZW combines various exciting properties to be applied in a full-scale process for arsenic recovery.