A novel b-FeOOH/NiO composite material as a potential catalyst for catalytic ozonation degradation of 4-chlorophenol

Abstract

In this study we report on the organic linker mediated fabrication and catalytic activity of a novel b-FeOOH/ NiO composite material for the first time. Four-chlorophenol (4-CP) was used as a target molecule to evaluate the catalytic activity of the composite material in ozonation reactions. Three different b-FeOOH loadings, labelled 2, 5 and 10% b-FeOOH/NiO composites were prepared. The 5% b-FeOOH/NiO composite material showed the highest activity in the composite structure. XRD, FTIR and TEM were used to characterise the composite structure. Evidence of a chemically bonded interface between b-FeOOH and NiO was apparent from the FTIR and TEM results. Adsorption of 4-CP on the catalyst surface was found to be negligible. First order reaction kinetics were used to describe the 4-CP degradation behaviour and the rate constants increased with increasing initial pH of the solution. No detectable amount of both Fe and Ni leaching into the solution was observed at a pH range of 10–2.3. After 20 min of the ozonation reaction, 85% of 4-CP was removed by the heterogeneous system as opposed to 47% by ozonation alone. The developed composite material exhibited good recyclability as the catalytic activity of the material could be recovered by calcination after use. A maximum of 66% of COD was removed just after 50 min of the catalytic ozonation reaction. The enhanced catalytic activity of the composite material was due to higher generation of OHc which was supported by photoluminescence (PL) experiments