Performance assessment of an analcime-C zeolite–ceramic composite membrane by removal of Cr(vi) from aqueous solution

Abstract

This article describes the synthesis of an analcime-C zeolite membrane on a ceramic support by in situ hydrothermal crystallization. A circular shaped ceramic support was firstly fabricated using low cost raw materials by a uni-axial pressing method and sintering process. Subsequently, the zeolite composite membrane was prepared with the repeated coating of analcime-C on the ceramic support through an in situ crystallization technique. The synthesized zeolite composite membrane was characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), porosity, average pore size and pure water permeability. The influence of the number of coatings on the characteristics of the zeolite membrane was also explored. The obtained results clearly demonstrate that the porosity, pore size and water permeability of the membrane decrease significantly with the multiple coating of zeolite over the ceramic support. The porosity, average pore size and pure water permeability of the zeolite membranes are estimated to be 38–24%, 285–155 nm and 2.18 × 10⁻⁷ to 4.53 × 10⁻⁸ m³ m⁻² s⁻¹, respectively for various coatings (1–3). Finally, the separation performance of three times coated zeolite membrane was evaluated by removal of chromium(VI) from aqueous solution by ultrafiltration (UF) at various operating conditions (applied pressure, concentration and pH). The maximum rejection of 84% is achieved at an applied pressure of 207 kPa. Moreover, the separation performance of membrane is better as compared to other membranes reported in the literature.