Preparation of high concentration polyaluminum chloride by chemical synthesis-membrane distillation

A method of direct contact membrane distillation (DCMD) with a self-made hollow polyvinylidene fluoride membrane was applied to prepare high concentration polyaluminum chloride (PAC1) with high Alb content based on chemical synthesis.The permeate flux and Al species distribution were investigated.The experimental results showed that the permeate flux decreased from 14 to 6 kg/(m2.hr) at the end of the DCMD process,which can be mainly attributed to the formation of NaC1 deposits on the membrane surface.The Alb content decreased slightly,only from 86.3％ to 84.4％,when the DCMD experiment finished,correspoudingly the Alc content increased slightly from 7.2％ to 8.5％,and the Ala content remained at 7％ during the whole DCMD process.A PAC1 with Alb content of 84％ at total aluminum concentration 2.2 mol/L was successfully prepared by the chemical synthesis-DCMD method.