Preparation Of Polyaluminum Chloride With Membrane Method And Study On Dye Wastewater Treatment

Polyaluminium chloride with excellent flocculation performance is an inorganic polymer flocculant. In the species of PAC solution, Alb is regarded as the most effective one in flocculation process, because it has higher charge, higher molecular weight and can maintain better stalility in the process of using. So the key to improve the flocculation performance of PAC is to increase the content of Alb.In the research, hollow fiber ultrafimembrane made from copoly (phthalazinone ether sulfone)(PPBES) was employed as lye distributor to prepare PAC. NaOH solution and AICl3solution flowed on both sides of the membrane, respectively. Under the transmembrane pressure, NaOH solution permeated gradually through the micropores of membrane into the AICl3solution. It can create a micro environment for the production of Alb, so it led to the increase of the Alb content in PAC solution.In the paper, the effects of concentration of AICl3solution, the Base value, the permea-tion rate of lye, lye concentration, the velocity of AICl3solution and molecular weight cut-off of membrane (MWCO) on the distribution of aluminum species were investigated. And aluminium-Ferron time-complexation colorimetry was used to measure the content of aluminum species. By the experiment, the optimal conditions of preparing PAC had obtained: the concentrations of AICl3solution and lye were1.25mol/L and0.5mol/L respectively, the Base value was1.9and permeation rate of lye was15.3mL/min. It also found that higher velocity of AICl3solution and smaller membrane MWCO were all favorable for the formation of Alb species. The content of Alb reached as much as81.1%.In the experiment, PAC was used to deal with Congo red and reactive brilliant blue X-BR dye wastewater to inspect its flocculation performance. And the effects of the adding volume of PAC, the Base value of PAC, the concentration of dye solution and pH value were investigated, respectively. The results showed that the adding volume had an optimal value, and higher content of Alb and higher concentration of dye solution were beneficial in improving the flocculation performance. The best interval of pH for PAC ranged from5to7.In the research, a magnified hollow fiber membrane module was made to synthesis PAC. and the preliminary exploration of process conditions was carried out. The effective area of the membrane is0.6m2. The results showed that the PAC prepared had a high content of Alb and showed a high flocculation ability to dye.