Abstract
This study aimed to assess the performance of three zeolite membranes in the removal of trivalent metal ions from aqueous solution using a cross-flow mode of operation. Three types of zeolite membrane, MCM-41, MCM-48 and FAU, were prepared on a low-cost, circular ceramic support by hydrothermal treatment. The three zeolite membranes were characterized by using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and contact angle measurements. The XRD results confirmed the formation of zeolites. The deposition of zeolite on the ceramic support and hydrophilicity of zeolite membranes were monitored by FESEM and contact angle measurement, respectively. The pore size of the MCM-41, MCM-48 and FAU membrane was found to be 0.173 μm, 0.142 μm, and 0.153 μm, respectively, which was lower than that of the support (1.0 μm). The fabricated zeolite membranes were used to investigate the separation behavior of trivalent metal ions (Al3+ and Fe3+) from aqueous solution at various applied pressures. It was observed that an increase of applied pressure leads to a slight decrease in the removal efficiency. Among the various zeolite membranes, the FAU membrane showed the maximum rejection of 88% and 83% for Fe3+ and Al3+ separation, respectively.
Highlights
Metal ions in wastewater are a serious environmental concern owing to their high toxicity and tendency to accumulate in living organisms (Mohammad et al )
We found the isoelectric point of the MCM-41, MCM-48 and FAU zeolite membranes to be 3.9, 3.2 and 3.8, which was determined using zeta potential measurement (Delsa Nano) (Wu et al )
MCM-41, MCM-48 and FAU zeolite composite membranes do not have a tendency for fouling and cake layer formation on the surface of the membrane in the removal of trivalent metal ions
Summary
Metal ions in wastewater are a serious environmental concern owing to their high toxicity and tendency to accumulate in living organisms (Mohammad et al ). These metals are non-biodegradable in the environment; environmental regulations are designed to reduce the level of concentration in wastewater to the safe limit specified by legislation. Conventional techniques for the removal of effluent coming from various sources of streams are liquid–liquid extraction, precipitation, adsorption and ion exchange (Kumar et al a, b) These methods are time consuming, laborious, expensive and cannot reduce the pollutants to the limit framed by legislation. Charged ultrafiltration membranes are gaining popularity in wastewater treatment due to their
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