Catalytic wet air oxidation of phenol over ultrasound-assisted synthesized Ni/CeO2–ZrO2 nanocatalyst used in wastewater treatment

Abstract

Non-noble metal Ni with different loadings was coated on precipitated CeO2–ZrO2 support by the sonochemistry method and examined for catalytic wet air oxidation of phenol. The structure of the nanocatalysts was determined by BET, FESEM, XRD, and FTIR analyses. The results showed non-uniform morphology of the nanocatalyst at lower Ni contents changed to homogenous morphology with spherical nano particles at higher Ni contents. While the size of NiO crystals remained constant with rising Ni content, the crystallinity of NiO significantly increased. If the crystallinity of NiO was 100% in 20%wt Ni/CeO2–ZrO2, the crystallinity of NiO in 5%wt Ni was found to be 41.13%. The average particle size in Ni(15%)/CeO2–ZrO2 was 77nm in which 85.71% of particle diameters were less than 100nm. Catalytic wet air oxidation of phenol with different Ni loadings indicated improvement of phenol destruction at higher amounts of active phase. Removal of phenol increased with increasing catalyst loading from 4 to 9.0g/l but further increase to 10g/l declined the catalyst reactivity.