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Thermal desorption of PCBs contaminated soil with calcium hydroxide in a rotary kiln
- Liu, Jie, Zhang, Hao, Yao, Zhitong, Li, Xiaodong, Tang, Junhong
- Chemosphere 2019 v.220 pp. 1041-1046
- calcium hydroxide, dechlorination, desorption, electrical equipment, polluted soils, polychlorinated biphenyls, synergism, toxicity
- In this study, thermal desorption was combined with the addition of calcium hydroxide to remediate polychlorinated biphenyls (PCBs) contaminated soil, collected from a storage point for PCB-contaminated capacitors and transformers. The thermal desorption test conditions were varied from 300 to 600 °C, both with blank soil and with 1% Ca(OH)2 added. The results showed that the synergistic thermal desorption was effective to removal most of PCBs. At 600 °C, the removal efficiency (RE) reached 94.0% in presence of Ca(OH)2, higher than that of 90.9% in blank soil. The dechlorination was significant when compared with blank soil. Ca(OH)2 effectively decreased both the sum and the toxic equivalence quantity (TEQ) value of the 12 dioxin-like PCBs, with the RE based on TEQ of 90.0%. Ca(OH)2 strengthened the removal, dechlorination and detoxication of PCBs. The synergistic effect factor proved the promotion did exist in the presence of Ca(OH)2.