Removal of 2,4‐dichlorophenol by aluminium/O₂/acid system

Abstract

Background Although the oxidative removal of organic compounds by the Al/O2/acid system has been previously studied, the in situ generation of reactive oxygen species (ROS) and its influencing factors are not well understood. 2,4‐dichlorophenol (2,4‐DCP) is one of the priority control pollutants and widely present in the environment. In this study, the oxidative removal of 2,4‐DCP by the Al/O2/acid system was investigated, especially the in situ generation of ROS and influencing factors. Results More than 90% of 2,4‐DCP was removed within 10 h in pH 2.5 solutions initially containing 10 g L−1 Al and 8.25 mg L−1 dissolved oxygen. The removal of 2,4‐DCP was acid and oxygen driven and was accompanied by the release of chloride ions. While the reduction of oxygen to H2O2 by Al was obtained only under conditions of pH < 4.0, the subsequent Al‐mediated transformation of H2O2 to •OH was achieved under pH < 5.0 conditions. Furthermore, five primary intermediates were identified and oxidation pathways of 2,4‐DCP by the Al/O2/acid system were proposed. Conclusions This work describes a potential method for the removal of 2,4‐DCP in aqueous environments. Oxygen levels and solution pH played important roles in the removal of 2,4‐DCP by Al/O2/acid system. © 2013 Society of Chemical Industry

Filtrates with Hydroxyl Radicals Prepared using Al + Acid + H2O2 for Removing Organic Pollutants

“…Aluminum is a good electron donor − and has a more negative redox potential [ E 0 (Al 3+ /Al 0 ) = −1.662 V] than iron [ E 0 (Fe 2+ /Fe 0 ) = −0.44 V], which has been used to generate hydroxyl and sulfate radicals in aqueous solution and degrade organic pollutants in the past few years. − However, there is a dense passive oxide film covering the Al particle surfaces to prevent the transport of electrons from the inner Al to outside target reactants. In order to improve Al reaction activity in aqueous solution, different methods are adopted to activate Al such as acid washing, adding polyoxometalate (POM), with the assistance of Fe­(II) ions, , mechanical ball milling, − and so on.…”

Oxidative degradation of Triton X-45 using zero valent aluminum in the presence of hydrogen peroxide, persulfate and peroxymonosulfate

“…In recent years, AOPs involving zero-valent metals such as zerovalent iron (ZVI) and zero-valent aluminum (ZVAl) for the removal of biochemically inert pollutants have received increasing interest [16][17][18][19][20][21]. Similar to ZVI, ZVAl exhibits a capacity to degrade organic pollutants under acidic pH conditions.…”