Enhanced adsorption and Fenton oxidation of 2,4-dichlorophenol in aqueous solution using organobentonite supported nZVI

The removal of organic persistent contaminants in the environment is a challenge due to their hydrophobic nature. In this work, the removal of 2,4-DCP based on the adsorption and Fenton oxidation was reported, where organobentonite (OB)-supported zero-valent iron nanoparticles (nZVI) generated a hydrophobic environment to enhance adsorption, as well as to reduce the aggregation of nZVI. Adsorption efficiencies of 2,4-DCP by organobentonites which modified with hexadecyl trimethyl ammonium chloride (DK1), octadecyl dimethyl benzyl ammonium chloride (DK3) and aminocaproic acid (DK5), were found to be 27.8, 25.3, 1.0 and 1.0%, while the degradation efficiencies of 2,4-DCP using nZVI/DK1, nZVI/DK3, nZVI/DK5 and nZVI/B were 73.5, 46.1, 27.1 and 25.7%, respectively. Characterization of nZVI/DK1 by SEM, EDS and XRD revealed that nZVI effectively supported the interlayer and did not change the layer structure of DK1, and no peaks of 2,4-DCP was observed by FTIR and GC-MS due to degradation. The degradation of 2,4-DCP fitted well to the Langmuir-Hinshelwood model, and about 80.24% of chemical oxygen demand (COD) was removed using nZVI/DK1, suggesting that enhanced removal was attributed to the synergetic effect between adsorption by DK1 and Fenton oxidation by nZVI as the catalyst. The high number of recycling times proves that nZVI/DK1 could be a potential material to degrade halogenated organic pollutants.