Preparation and adsorption of mesoporous TiO_2 membranes

A stable TiO2sol was synthesized from titanium isopropoxide by colloidal sol-gel route.Mesoporous TiO2 membranes were prepared with tubular Al2O3 microfiltration membrane of 100nm pore size as support by dip-coating method.The effect of preparation process on integrity and pore structure of mesoporous TiO2 membrane was studied in detail.In addition,the absorption of acid orange 7and methylene blue onto unsupported mesoporous TiO2 membrane was researched.Defect-free mesoporous TiO2 membranes were obtained from TiO2sol added appropriate amount of PVA and HPC as binder by time-controlled dip-coating followed by calcination at 450℃for 1h.The thickness of TiO2 membrane was about 0.5μm and the pore size distributes in the range of 3-10nm.The absorption of acid orange 7and methylene blue onto mesoporous TiO2 membrane varies with pH value.It implies that adusting pH value may decrease membrane fouling caused by the adsorption.