Effect of iron/aluminum hydrolyzed precipitate layer on ultrafiltration membrane

In order to fully understand the effect of iron/aluminum hydrolyzed precipitate layer on ultrafiltration (UF) membrane, both hydrolyzed precipitate layers on a flat sheet UF membrane surface were investigated. The results showed that the aluminum hydrolyzed precipitate layer was much better than that of the iron hydrolyzed precipitate layer on protecting the UF membrane. X-ray diffraction (XRD) demonstrated that the structure of the aluminum precipitate layer was amorphous. Although the precipitate layer of aluminum sulfate hydrate could cause a slight flux decline, it improved the protection of the UF membrane to some extent. The rejection of different pollutants with Al precipitate layer was much higher than that without Al precipitate layer and many humic acid (HA)/bovine serum albumin (BSA) with different molecular weights could be adsorbed by the Al precipitate layer, especially for those with larger molecular weight. The rejection of 1:1 (by weight) HA/BSA mixture was higher than that of only HA or BSA in the presence of the precipitate layer of aluminum sulfate hydrate.