Liquid-phase hydrodechlorination of trichloroethylene driven by nascent H2 under an open system: Hydrogenation activity, solvent effect and sulfur poisoning

Junfeng Niu , Weilai Wang , Fan Zhang , Yunfei Zhang , Lei Xu , Yuansheng Pei


Received November 14, 2020,Revised , Accepted February 10, 2021, Available online March 02, 2021

Volume 33,2021,Pages 96-106

Hydrodechlorination is a promising technology for the remediation of water body contaminated with trichloroethylene (TCE). In this work, the liquid-phase hydrogenation of TCE by Raney Ni (R-Ni) and Pd/C under an open system have been studied, in which nascent H2 (Nas-H2) generated in situ from the cathode acted as a hydrogen source. Experimental results showed that TCE was completely eliminate from the solution through the synergistic effects of hydrodechlorination and air flotation due to the formation of continuous micro/nano-sized Nas-H2 bubbles from the cathode. Furthermore, the effects of inorganic anions and organic solvents on R-Ni and Pd/C hydrogenation activity were investigated, respectively. The results showed that NO3 and acetonitrile can form a competitive reaction with TCE; Sulfur with lone-pair electrons will cause irreversible poisoning to these two catalysts, and have a stronger inhibitory effect on Pd/C. This work helps to realize the separation of volatile halogenated compounds from water environment and provides certain data support for the choice of catalyst in the actual liquid-phase hydrogenation system.

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