Surfactant induced ultrafiltration of heavy metal ions from aqueous solutions using a hybrid polymer–ceramic composite membrane

Abstract

A low-cost ceramic membrane was coated with cellulose acetate (CA) using different polymer concentrations and dipping durations. The porosity of the membrane decreased considerably (from 58.4 % to 12.1 %) with an increase in polymer concentration from 2.5 to 10 wt. %. The values of the porosity increased and layer thickness decreased slightly with a decrease in dipping time (from 60 s to 15 s). The membrane prepared using 5 wt. % CA in acetone and 45 s dipping duration (T-3) had a polymer separation layer of thickness 14.2 µm and was found to be optimal with 51.8 % porosity, 35 nm pore diameter and a liquid (water) permeability of 7.39 × 10–10 m3/m2·s·Pa. This membrane was applied for micellar enhanced ultrafiltration of three heavy metal ions, namely, Cu(II), Cr(VI) and Ni(II). The prepared membrane (T-3) was highly effective in ultrafiltration applications as evidenced from complete rejection (≈ 100 %) of cetylpyridinium chloride (CPC) along with satisfactory removal (>99.7 %) of metal ions.