The abatement of chlorophenols is of great environmental importance. Though Fe-0 can activate persulfate (PS) to improve performance, our findings proved that pre-magnetized Fe-0 (Pre-Fe-0) could significantly enhanced the degradation and dechlorination of 2,4-dichlorophenol (2,4-DCP), and this Pre-Fe-0/PS process was more efficient than Fe(II)/PS. The Fe-0 before and after magnetization was characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD), suggesting the acceleration of Fe2+ release after magnetization. The effects of some important operating parameters such as Fe-0 dosage, PS dosage, pH, and initial 2,4-DCP concentration on the 2,4-DCP degradation and dechlorination by Pre-Fe-0/PS were investigated and compared with that of Fe-0/PS, observing a 1.9-5.2-fold enhancement in the degradation rate of 2,4-DCP. Although SO4- was the dominant active species responsible for 2,4-DCP degradation in two processes, pre-magnetization could promote more OH generation. Identified by GC-MS and IC, the degradation intermediates such as 4-chlorophenol (4-CP), 2-chlorophenol (2-CP), phenol, and some carboxylic acids were detected, and possible degradation pathway was proposed. This Pre-Fe-0/PS process was also efficient for 4-chlorophenol and chlorobenzene degradation, obtaining a 5.2 and 3.2 folds enhancement, respectively. This work demonstrated that such a Pre-Fe-0/PS would be very promising and environmental-friendly for organics degradation and dechlorination since pre-magnetization required no extra energy source while the introduction of Pre-Fe-0 was rather simple and no need to change the present treatment system. (C) 2016 Elsevier B.V. All rights reserved.