Application of polyaluminum chloride prepared by a membrane reactor to dyestuff wastewater

In this study polyaluminum chloride (PAC) has a high Alb content, 80.1%. It was the most efficient species of PAC. PAC was synthesized with a membrane reactor which made of a hollow-fiber (HF) ultrafiltration membrane (UFM). The UFM was made from PPESK, a novel membrane material with properties of excellent thermal, chemical and mechanical stability. In this reactor, a sodium hydroxide solution permeated slowly through the microspores of HF UFM into AlCl3 wastewater. Because the alkali drop size was reduced to nano-scale, it is beneficial to bring a dramatic reduction of localized super-saturation and enhancement of the Alb quantity. The purpose of the study is to prepare liquid PAC utilizing the aluminum chloride wastewater as a raw material through a membrane reactor system and to evaluate the performance by using an orthogonal array of the design of experiments (OADE) on the sedimentation to four different dyestuffs: Titan Yellow, Methyl Orange, Food Yellow and Procion Red. The results show that PAC prepared by the membrane reactor has higher Alb and better flocculation properties to different dyestuffs than the commercial PAC, whose average sedimentation can exceed 96%.