Purification of chlorine-containing wastewater using solvent extraction

The extraction of chloride from wastewater using trioctylamine (TOA) diluted in sulfonated kerosene as the extractant has been investigated. The results showed that the optimal operating conditions of the extraction chloride were ascertained by univariate experiment, and the best removal rate 79.11% was determined. The McCabe-Thiele diagram demonstrated that 98.41% of chloride could be extracted in a four-stage counter-current simulation and less than 0.0169 mol/L chloride remained in aqueous, which has reached the discharge requirements of enterprises in Guangxi, China. Loaded organic phase was stripped effectively by 30 wt% NaOH and a five-stage counter current extraction confirmed to eradicate 4.59 mol/L chloride (>99.9% stripping efficiency). Furthermore, the reutilization of regenerated organic phase attains the efficiency of fresh organic phase. The superiority of solvent extraction, i.e., remarkable effect for high concentration wastewater, high separation efficiency and renewability have been authenticated, validating it is expected to be an alternative method in the field of wastewater treatment. Meanwhile, this work provides new ideas for the removal of other intractable inorganic anions. (C) 2020 Elsevier Ltd. All rights reserved.