Advantage of solvothermal procedure for polychlorinated biphenyls removal from e-waste contaminated site

Abstract

a b s t r a c tPolychlorinated biphenyls (PCBs) are environmentally persistent, toxic, bioaccumulative and recalcitrant. In this study, aged PCBs from e-waste contaminated site were respectively subjected to Soxhlet and solvothermal treatments. The results indicated that solvothermal method was much more predominant for PCBs removal than traditional Soxhlet method. Sequential Soxhlet-solvothermal experiment demonstrated that Soxhlet unextractable (bound) PCBs were efficiently removed by solvothermal procedure due to enhanced solvating effects of organic solvents. The key point was that bound PCBs in the aged soil were partitioned in different components of soil organic matter, e.g., the solvothermal removal amounts of I-V PCBs (sum of PCB8, PCB18, PCB28, PCB44, PCB66) from fulvic acid (FA), humic acid (HA), bound humic acid (bound HA), bound lipids and mineral fraction were 0.4, 40.8, 28.4, 19.8, and 10.6%, respectively. It was found that isopropanol was the most effective solvent for PCBs removal. The optimum performing temperature, time and liquid to solid ratio for PCB8, PCB18, PCB28, PCB44, and PCB66 were 170 • C, 8 h and 10:1, respectively. As for higher molecular weight PCB congeners, these conditions were 150 • C, 10 h and 15:1. Soil organic matter content was unchanged after solvothermal treatment indicating that soil fertility remained after the removal process. This work provides a more clean process for effective treatment of soils contaminated by persistent organic pollutants (POPs) in comparison to traditional methods.

Removal of brominated flame retardant from electrical and electronic waste plastic by solvothermal technique

“…Further studies [13] indicated that the removal efficiency of BFRs by solvent extraction was better than that of Sc-CO 2 modified with solvents. Recently, we have revealed that solvothermal process was a powerful method to remove organic pollutants from soil matrix [14]. As a consequence, we applied this technique to the removal of BFRs from E&E waste plastic.…”

Hydrodechlorination of PCDD/PCDF/PCB contaminants by simple grinding of contaminated soils with a nano‐size calcium reagent

“…First-generation decontamination procedures were designed to separate dioxins and facilitate their subsequent hydrodechlorination. Consequently, thermal desorption [20][21][22], steam distillation [23], and solvent extraction [24][25][26] were used. Although hydrodechlorinating thermal treatments have been applied to fly ash [27][28][29][30], no application of this process, either in situ or ex situ, has been reported for soil.…”