HOU Zhendong, LIN Xi, RUAN Huimin, LI Hongdi, SHEN Jiangnan, GAO Congjie
With the rapid development of massive industrial productions, the emission amount of the industrial wastewater is increasing sharply, most of which contains sulfate. The excessive emission of sulfate will cause serious pollution and damage to the environment water body. To solve this problem, in this paper, the sodium sulfate waste is used as the raw material, a new technology of the bipolar membrane electrodialysis is adopted, thus, the wastewater containing sulfate is reasonably reutilized and converted efficiently into the corresponding acid and alkaline. In the experiment, the effects of the current density, the feed concentration and the initial pH concentration on the membrane reactor are investigated, and the performances of the two ion-exchange membranes are compared. It is shown that in the experimental range the yield of the sodium hydroxide reaches 84.08%, the average current efficiency of the process reaches 54%, the energy consumption reaches 5.29 kW·h/kg, and the sodium hydroxide yield and the process energy consumption rise with the increase of the current density. When the current density is constant, a higher raw material concentration can make the membrane reactor stay at a relatively lower level during the experiment, which reduces the energy consumption. The right amount of the initial acid and alkali can reduce the energy consumption, but the current efficiency will decrease.
