Evaluation of Pentachlorophenol Removal from Treated Wood by Hydrothermal Carbonization and Pyrolysis.

Abstract

Pentachlorophenol (PCP) was officially banned for use in wood treatment in October 2023, due to its potentially negative impact on both human health and ecosystems. This study evaluated the feasibility of hydrothermal carbonization (HTC) and pyrolysis for the degradation and removal of PCP, using southern yellow pine sawdust spiked with 3% w/w PCP/sawdust as a model system. Different temperatures were examined for both HTC and pyrolysis processes, while pH adjustment was applied only in the HTC process to assess the influence of pH. The results indicate that HTC initiates the dechlorination of PCP at 180 °C, with complete degradation occurring at temperatures above 220 °C. In contrast, pyrolysis effectively removed PCP from the solid phase even at lower temperatures. Additionally, chemical activation of the hydrochar using KOH not only significantly improved its surface properties but also ensured the complete elimination of chlorinated compounds.