Degradation of 2,4-dichlorophenol by activating persulfate and peroxomonosulfate using micron or nanoscale zero-valent copper

The ability of persulfate (PS) and peroxymonosulfate (PMS) activated by micron or nanoscale zero-valent copper (ZVC or nZVC) to degrade 2,4-dichlorophenol (2,4-DCP)was quantified under various conditions. Mechanism investigation revealed that PS and PMS accelerated the corrosion of ZVC or nZVC to release Cu+ under acidic conditions. The in-situ generated Cu+ further decomposed PS or PMS to produce SO4 center dot- and (OH)-O-center dot, which then dramatically degraded 2,4-DCP. The k(obs) for 2,4-DCP removal followed pseudo-first order kinetics, kobs of ZVC/PMS and nZVC/PMS systems were 10 similar to 30 times greater than these in ZVC/PS and nZVC/PS systems. The nZVC/PMS system was most effective to remove 2,4-DCP which even did better than the nZVI/PMS system, with rate constant values ranging from 0.041 to 1.855 min(-1). At higher pH ZVC is. ineffective, but nZVC can activate PS and PMS to significantly degrade 2,4-DCP at pH up to 7.3. The 2,4-DCP degradation pathway was found to involve dechloridation, dehydrogenation, hydroxylation, ring open and mineralization. 56.7% and 45.3% of TOC removals were respectively obtained in the ZVC/PMS and nZVC/PMS systems within 120 min. This study helps to comprehend the application of zero-valent metals in reactive radicals-based oxidation processes and the reactivity of Cu+ as an activator of PS and PMS. (C) 2017 Elsevier B.V. All rights reserved.