The Dechlorination of 2,4-Dichlorophenol by Zero-Valent Iron

Abstract

During the dechlorination of 2,4-dechlorophenol(2,4-DCP) by zero-valent iron(ZVI), pH was one of the important factors affecting the dechlorination. The adsorption of chlorophenol by ZVI and the dechlorination rate were influenced by pH. The dechlorination of 2,4-DCP by ZVI was pseudo-first-order reaction, the pseudo-first-order reaction rate constant (K <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">SA</sub> ) were respectively 0.1773 h <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> , 0.2943 h <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> , 0.062 h <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> and 0.0525 h <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> when pH were 2.5, 4.2, 5.8, and 10.0. According to GC/MS, it was concluded that the process of 2,4-DCP's dechlorination via ZVI was: 2, 4-DCP → 2-CP or 4-CP → phenol. The mechanism of dechlorination of 2,4-DCP by ZVI could be direct reduction on the surface of iron or reduction by atomic hydrogen or the conjunct action of them.