Research progress on removal methods of Cl- from industrial wastewater

The discharge of large quantities of chlorine-containing wastewater (as high as 70,000 mg/L) in several metallurgical, chemical and other industries is a serious and widespread environmental problem that demands urgent attention from the scientific community. The complex composition of chlorine-containing wastewater makes the removal process difficult, green and sustainable treatment of chlorine-containing wastewater has attracted widespread attention. Through in-depth analysis of various mechanisms, optimum parameters, advantages and disadvantages, this review attempts to comprehend the state-of-the-art knowledge and insights of technologies for Cl- removal. Both the traditional methods and new enhanced methods can make the removal rate of Cl- reach more than 90%. In addition, the developmental trends and potential improvements to these approaches are also presented. Currently, chemical precipitation method is the most common and efficient Cl- removal method, for which advanced oxidation method is regarded as an effective means of improvement. Supported by the efforts on continuous development of new materials, the effective combination of existing methods is most likely to achieve a significant breakthrough, to achieve a green and sustainable management of chlorine-containing wastewater.