Efficient degradation of 4-chlorophenol over zirconium, nitrogen and sulphur doped cobalt nanoferrite catalysts

Abstract

Cobalt ferrite and zirconium doped cobalt ferrite were prepared by coprecipitation method. Nirogen and sulphur ions were doped to it by wet impregnation and co precipitation techniques. The efficiency of the samples towards catalytic wet peroxide oxidation of 4-chlorophenol was checked. Doping increased the catalytic efficacy of cobalt ferrites towards the reaction; zirconium being the most efficient dopant. Complete conversion of 4-chlorophenol with appreciable reduction in chemical oxygen demand(COD) was noted at 50 °C with pollutant to hydrogen peroxide ratio of 1:15. Surface area and nature of the catalyst active surface played deciding role in the oxidation rreaction. The mechanism followed a heterogenous free radical catalysed path as evidenced from metal leaching and radical scavenging studies. The catalysts were magnetically recoverable and stable on repeated uses.