Cu(II)-kaolinite and Cu(II)-montmorillonite as catalysts for wet oxidative degradation of 2-chlorophenol, 4-chlorophenol and 2,4-dichlorophenol

Cu(II) was introduced into kaolinite and montmorillonite by impregnation and the resultant materials were calcined at 723 K for 360 min. Both Cu(II)-kaolinite and Cu(II)-montmorillonite were used as catalysts for oxidizing three chlorinated derivatives of phenol in water in presence and in absence of H2O2. The catalysts were characterized with AAS, XRD, surface area, SEM and FT-IR measurements. Wet oxidation of 2-chlorophenol, 4-chlorophenol and 2,4-dichlorophenol in presence of the catalysts was followed by varying mole ratio of reactant and H2O2, catalyst load, temperature, reaction time, initial concentration of chlorophenols and pH. The followed first order kinetics and the activation energy was 32.98 kJ mole−1, 43.54 kJ mole−1 and 87.34 kJ mole−1 with Cu(II)-kaolinite and 27.69 kJ mole−1, 40.39 kJ mole−1 and 73.29 kJ mole−1 with Cu(II)-montmorillonite respectively for 2-chlorophenol, 4-chlorophenol and 2,4-dichlorophenol. Conversion increased with catalyst loading but very higher loading was not much effective. Conversion was more at lower pH, but was also sufficient at the pH of the aqueous chlorophenols solutions. Leaching of Cu(II) from the catalysts at this pH was not much to affect the quality of water.