Formation of Mg(OH)₂ dynamic membranes for oily water separation: effects of operating conditions

Formation of a new type of Mg(OH)₂ dynamic membrane on α-Al₂O₃ porous ceramic tubes was investigated. Attention was paid to the effects of operating conditions on the cake layer during formation of a dynamic membrane. The influence of operating parameters such as suspension concentration, cross-flow velocity and transmembrane pressure on the formation was different. It is difficult to form a satisfactory dynamic membrane under the conditions of shorter formation time, higher cross-flow velocity and lower suspension concentration. An increase in transmembrane pressure and suspension concentration resulted in an increase in the dynamic layer and an increase in TOC rejection. However, increasing the cross-flow velocity resulted in a decrease in the dynamic layer and TOC rejection. Under certain conditions, the prepared membrane had a uniform and compact structure. It showed good performance in separating oil from water using a model oil emulsion. A TOC rejection of more than 98% and a permeate flux of more than 1 L·m^-2·h^-1·kPa^-1 were obtained in a batch concentration test.