Journal of Hazardous Materials ( IF 9.038 ) Pub Date : 2020-08-01 , DOI: 10.1016/j.jhazmat.2020.123545 Liangjing Zhang; Peng Lv; Yuan He; Shiwei Li; Jinhui Peng; Libo Zhang; Kaihua Chen; Shaohua Yin
The chloride salt derived from the rare earth smelting wastewater was effectively dislodged using Friedel’s salt precipitation assisted with ultrasonic enhancement. Various single factors such as the reagent ratio, temperatures, reaction time and agitation speed were determined and investigated systematically. Results showed that the optimal single-stage removal efficiency were 88.22 % and 80.89 % with and without ultrasonic strengthen, respectively. The particle size distribution, morphology and elemental analysis of the precipitation were carried out by TEM, SEM, EDS and XRD analysis. These results revealed that the effect of ultrasonic has been given prominence to the removal efficiency of chloride salt. It is attributed to the cavitation and mechanical disturbance effect of ultrasound. In order to further decline the chloride, a two-stage de-chlorination carried out, the result indicated that the concentration of chloride was 120 mg/L and 430 mg/L with and without ultrasonic strengthening afterwards two-stage de-chlorination, respectively. The chloride concentration can fully meet the effluent concentration requirement under the effect of ultrasonic enhancement.