Synthesis of clay/Fe/ZSM-5 composite membrane for chromium (vi) removal from aqueous media and its electrochemical performance

Abstract

The present study explores the potential use of a Clay/Fe/ZSM-5 zeolite membrane as an effective platform for Chromium (VI) filtration. The raw clay sourced from Wadi Haqil Ras Al-Khaimah-UAE was utilized for fabricating the clay support sintered at 1000°C. Clay powder with a granulometry range of 125 µm ≤ Φ ≤ 250 µm, was obtained through crushing and sieving with ASTM sieves and used to prepare the clay support. The Fe/ZSM-5 zeolite was synthesized via the hydrothermal method, using tetrapropylammonium bromide (TPABr) as an organic structure-directing template. The characterization of both the clay support sintered at 1000°C and Fe/ZSM-5 zeolite membrane was conducted through various techniques, including XRD, FTIR, FE-SEM coupled with EDS, and XPS analysis. Notably, the support exhibited a relatively high deionized water flux, stabilizing at 140 L.m−2.h−1 after 120 min of operation, indicating excellent permeability. FE-SEM observations confirmed that Fe/ZSM-5 consisted primarily of granular particles with an orthorhombic crystal lattice, aligning with its crystallinity demonstrated by XRD analysis. The filtration tests for Cr(VI) solutions, conducted using a flow loop designed for cross-flow filtration, demonstrated retention rates of 23 % and 40 % for the clay support and Fe/ZSM-5 zeolite membrane, respectively, after a working time of 120 min. These results suggest the potential of Fe/ZSM-5 zeolite as an effective alternative adsorbent for removing Cr(VI) from wastewater, showcasing outstanding performance in this application. The Clay support and Fe/ZSM-5 zeolite membrane materials were used as electrodes for cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in [Fe(CN)6]3-/4-/0.1 M KCl solution, and Fe/ZSM-5 zeolite membrane material exhibited high electrochemical charge transfer compared to the clay support material.