Catalytic ozonation of succinic acid in aqueous solution using the catalyst of Ni/Al2O3 prepared by electroless plating-calcination method

A catalyst of the Ni/Al2O3 was prepared by electroless plating-calcination (EPC) method using Al2O3 support for catalytic ozonation. To evaluate the catalytic activity of Ni/Al2O3, the O-3 + Ni/Al2O3 system was set up to degrade succinic acid (SA). First, the key preparation parameters (i.e., plating time, calcination temperature and calcination time) of Ni/Al2O3 and operational parameters (i.e., initial pH, ozone flow rate and the catalyst dosage) of O-3 + Ni/Al2O3 system were optimized, respectively. The maximum SA removal (100%) and total organic carbon (TOC) removal (84.7%) were obtained under the optimal conditions. Meanwhile, characteristics of the Ni/Al2O3 catalysts prepared by EPC method and traditional impregnation-calcination (IC) method were studied comparatively through scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), Brunauer-Emmet-Teller (BET), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD), respectively. The results show that nickel oxides (NiO) was uniformly deposited on the Al2O3 surface when Ni/Al2O3 was prepared by EPC method. On the contrary, when Ni/Al2O3 was prepared by IC method, nickel oxides were heterogeneously, rough and loose distributed on the surface of Al2O3 substrate. Furthermore, Ni/Al2O3 prepared by EPC possessed higher BET surface areas, higher pore volumes and smaller pore size distribution than Ni/Al2O3 prepared by IC. Finally, the catalytic mechanism of the O-3 + Ni/Al2O3 system was proposed according to the characterization of Ni/Al2O3 prepared by EPC, radical scavenging studies, hydroxyl radical (HO center dot) and H2O2 detection experiments. Collectively, these results suggest that the EPC method was a promising technology for catalyst preparation of Ni/Al2O3 with high catalytic performance and the Ni/Al2O3 should be proposed as a promising catalyst for the decomposition of ozone.