Lurgi-Thyssen dust catalytic thermal desorption remediation of di-(2-ethylhexyl) phthalate contaminated soils

Fe2O3-assisted pyrolysis has been demonstrated to be a cost-effective thermal desorption (TD) technology . Lurgi-Thyssen dust (LTD) is a type of steel slag waste that contains a large amount of Fe2O3. In this study, to reduce energy consumption, LTD was added to contaminated soil to evaluate the feasibility of enhancing the TD removal efficiency of di-(2-ethylhexyl) phthalate (DEHP). The DEHP removal rate increased by 22.39% after adding 2% LTD at 200 °C for 20 min. Because of the catalytic pyrolysis of LTD, DEHP was pyrolyzed to form three types of short-chain esters: mono-(2-ethylhexyl) phthalate (MEHP), di (2-methylbutyl) ester, and methyl 2-ethylhexyl phthalate. The pyrolysis products of DEHP were less toxic and did not affect soil reuse. When the DEHP removal rate was 87.10%, LTD addition decreased the temperature and residence time of TD and alleviated the effect of TD on the soil physicochemical properties . Additionally, the desorption of DEHP from soil fitted the pseudo-second-order kinetic model well. Thus, the addition of LTD to contaminated soil enhanced the efficiency of TD remediation. Moreover, this study could provide a practical and economical strategy for LTD reuse.