Sulfuric acid recovery from titanium white (pigment) waste liquor using diffusion dialysis with a new series of anion exchange membranes — static runs

In this paper, a new series of anion exchange membranes have been produced from linear engineering plastics poly(2,6dimethyl-1,4-phenylene oxide) (PPO) by conducting the processes of bromination, chlomethylization and amination. By using this series of membranes, the runs of sulfuric acid recovery from titanium white waste liquor were experimentally conducted. The effects of some important factors such as ion exchange capacity, content of benzyl-halogen and the relative compositions of the liquor were experimentally investigated on the membrane dialysis process. It was found that the acid recovery rate was improved by benzyl substitution, while the selectivity improved by aryl substitution. By properly balancing them and adjusting the compositions of feed, both higher selectivity and acid recovery can be achieved. A comparison is made with a commercial diffusion dialysis membrane in China. © 2001 Elsevier Science B.V. All rights reserved.