Removal of chloride ions from desulfurization wastewater by ZnMgAl-LDHs

Desulfurization wastewater containing high chloride ions will cause serious harm to pipelines, concrete buildings and the environment.Therefore, it is necessary to remove the high concentration of chloride ions in desulfurization wastewater.In this work, Zn-Mg-Al ternary hydrotalcite (ZnMgAl-LDHs) was prepared by chemical precipitation method and used to remove chloride ions from desulfurization wastewater.Batch adsorption experiments showed that the removal efficiency of chloride ions by ZnMgAl-LDHs reached 92% when the dosage was 8 g/L and pH was 7.0.Additionally, sulfate, carbonate, silicate and phosphate inhibited the removal of chloride ions by ZnMgAl-LDHs.Notably, the adsorption of chloride ions by ZnMgAl-LDHs was mainly controlled by chemical interactions, such as ion exchange and complexation.After three times of NaOH regeneration, the removal efficiency of chloride ions by ZnMgAl-LDHs could still be maintained at more than 80%.These results indicated that ZnMgAl-LDHs can effectively remove chloride ions from desulfurization wastewater.