Preparation of γ-Al2O3 membranes for ultrafiltration by reverse micelles-mediated sol-gel process

Abstract Sol-gel process was modified by reverse micelles (RMs) for the preparation of γ-Al2O3 ultrafiltration (UF) membranes and their applications in the efficient rejection of methyl blue and bovine serum albumin were explored. The optimized boehmite sol with a narrower particle size distribution and better sphericity was synthesized by using cetyltrimethyl ammonium bromide RMs as microreactors and was dip-coated on α-Al2O3 microfiltration substrates to prepare γ-Al2O3 UF membranes. It was found that not only the sol particle size, it's distribution and morphology had also an important effect on the pore size, pore size distribution, porosity and pore volume of the membrane. Additionally, the as-prepared membranes with a MWCO of 8 kDa exhibited a narrow pore size distribution (4.8–6.8 nm), relatively high pure-water flux (30.4 L/(h m2 bar)) and excellent rejection for bovine serum albumin and methyl blue with the maximum rejection rate of 96.2% and 96.8% respectively.