Molten NaOH-KOH assisted thermo-chemical detoxification of waste salt containing hazardous organics

Thermo-chemical conversion (TCC) is an effective strategy in the detoxification of waste salt (WS) containing hazardous organics, which can be enhanced by molten salt, e.g., molten NaOH-KOH. However, the microscopic process remains largely unclear. With the WS collecting from a pesticide enterprise, this study comprehensively investigated the pyrolysis and combustion behaviors based on TG and FTIR. Particularly, molten NaOH-KOH mediation was explored. The results showed that combustion appeared to be more advantageous than pyrolysis for WS detoxification. Moreover, attributing to the enhanced heat transfer and catalytic activity of molten NaOH-KOH, the detoxification was promoted, manifested as a decrease in the peaked temperature of organic reactions (from 192 ℃ to 147 ℃). In addition, the emissions of C x H y , CO, and SO 2 decreased by 55.4 %, 88.2 %, and 74.1 %, respectively, due to the trapping effect by molten NaOH-KOH. Afterwards, continuous operation was conducted, and the results showed that the total organic carbon of the treated WS reduced evidently by 75.9 %, indicating stable and satisfactory performance. This study is of significance for understanding the WS transformation during TCC, especially when the molten salt is involved. The effective suppression of gas emissions under controlled conditions and the stable performance during continuous operation demonstrate the potential of this process for large-scale applications in the future.