Preparation of catalytic polyether sulfone coated ceramic membrane for reduction of hexavalent chromium

A novel catalytic polyether sulfone coated ceramic membrane was prepared for catalytic reduction of chromium (VI) to chromium(III). First, ceramic membrane (CM) was prepared as a support with blending of 10 % w/w nanomagnetite using kaolin. Second, polyether sulfone (PES) with three different nanomagnetite concentration (10, 20, 30 % w/w) was coated on the ceramic membrane support using phase inversion method. The prepared novel catalytic polyether sulfone coated ceramic membrane was used as a catalytic reactor to convert chromium (VI) to chromium(III). The effect of nanomagnetite concentration (10, 20, 30 % w/w), applied pressure (1, 2, 3 bar), and solution pH (3, 5, 7) on Cr(VI) reduction and permeate flux was systematically investigated. A dead-end filtration system was used for filtration and the vessel contained the chromate solution (10 mgCr(+6)/L). The maximum chromium(VI) reduction (96.2 %) were obtained at 1 bar pressure and pH:3 for PES20-CMR10 membrane, which indicated 20 % w/w PES and 10 % w/w CM. The results showed that the catalytic polyether sulfone coated ceramic membrane effectively reduced the chromium(VI) to levels below 0.38 mg/L without losing activity in repetitive 3 runs. The catalytic membrane was characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET), atomic force microscopy (AFM), scanning electron microscopy (SEM), and contact angle instruments. The results demonstrated that the chromium(VI) could be completely eliminated by the novel catalytic polyether sulfone coated ceramic membrane.

Automated summary

A novel catalytic polyether sulfone coated ceramic membrane was successfully prepared for catalytic reduction of chromium (VI) to chromium(III) with a reduction rate of 96.2%. The effects of various factors on chromium reduction and permeate flux were systematically investigated, demonstrating the membrane's stability in reducing chromium(VI) concentrations to below 0.38 mg/L.