Reaction of activated carbon zerovalent iron with pentachlorophenol under anaerobic conditions

Abstract

Pentachlorophenol (PCP) is a toxic pollutant and often treated with zero-valent iron (ZVI) in groundwater. In order to improve the reaction rate and selectivity, activated carbon modified zero-valent iron to degrade PCP. This study investigated the effects of carbon loading on the structure, specific surface, and hydrophobicity of AC-ZVI. The results showed that water contact angle and specific surface, which determined hydrophobicity and adsorption capacity, account for the reactivity and selectivity of AC-ZVI during the reduction degradation of the contaminant PCP. The pseudo-first-order kinetic degradation rate of AC-ZVI is 7.44x10(-2) h(-1), and two times higher than for ZVI (3.21x10(-2) h(-1)). Besides, as the [C/Fe]measured weight ratio increased, the ratio of K-PCP/K-H2 increased from a minimum of 0.218% to a maximum of 0.533%. Based on the pathway of AC-ZVI and PCP, the reduction degradation mechanism of PCP was discussed. These findings can contribute to the rational design of AC-ZVI with properties tailored to a variety of halogenated organics in groundwater remediation. (C) 2021 Elsevier Ltd. All rights reserved.