Molybdenum disulfide modified microscale zero-valent iron (MoS-mZVI) for enhanced trichloroethylene dechlorination

Abstract

The potential of microscale zero-valent iron (ZVI) for dechlorinating chlorinated hydrocarbons holds promise in pollution remediation. However, Fe0 passivation presents a challenge, leading to slow dechlorination and the buildup of hazardous incomplete dechlorinated intermediates. To address these concerns, we introduce molybdenum disulfide (MoS2)-modified microscale ZVI (MoS-mZVI). Our study demonstrates the significant enhancement of trichloroethylene (TCE) dechlorination by MoS-mZVI compared to standard mZVI. Remarkably, the optimal Fe/MoS2 molar ratio of 20 in MoS-mZVI achieves a remarkable 26.8-fold acceleration in TCE removal compared to mZVI. Acetylene emerges as the primary intermediate in TCE dechlorination by MoS-mZVI, peaking at 38%, accompanied by major end products including ethene (45%) and ethane (31%). Importantly, the MoS-mZVI-20 system avoids toxic byproducts, diverging from the dichloroethylene accumulation observed in the mZVI system. Notably, electron utilization efficiency shows significant improvement, with MoS-mZVI reaching 65.6% compared to mZVI's 7.2%. Furthermore, MoS2′s selective OH- adsorption triggers pH reduction, mitigating mZVI passivation and optimizing its reactivity. This innovative approach highlights the effectiveness of MoS2-modified microscale ZVI as an environmentally friendly solution for enhancing TCE dechlorination processes.