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

Sol-gel process was modified by reverse micelles (RMs) for the preparation of γ-Al 2 O 3 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-Al 2 O 3 microfiltration substrates to prepare γ-Al 2 O 3 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 m 2  bar)) and excellent rejection for bovine serum albumin and methyl blue with the maximum rejection rate of 96.2% and 96.8% respectively.