Reactivity of carbon spheres templated Ce/LaCoCuO in the microwave induced HO catalytic degradation of salicylic acid: Characterization, kinetic and mechanism studies.

Three-dimensionally (3D) meso-macroporous LaCoCuO-supported Ce (xCe/LCCO; x = 0-15 wt%) were prepared by in-situ carbon spheres-templating strategy. Structural and physicochemical properties of the materials were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and vector network analysis (VNA), and their microwave (MW) catalytic activities towards salicylic acid (SA) degradation were evaluated. It was found that appropriate Ce doping amount (x = 10 wt%) was beneficial for the generation of high-quality 3D meso-macroporous structure, good MW absorbing ability, high active oxygen species concentration and strong interaction between Ce and carbon spheres templated LaCoCuO, resulting in the high MW catalytic activity. Significantly, SA degradation efficiency reached 93.8% under optimal conditions with initial pH of 6.0, MW power of 480 W, catalyst dosage of 6.0 g·L, HO concentration of 2 mL·L and SA concentration of 10 mg·L. The obtained kinetic equation followed the pseudo-first-order model. Radical scavenger measurements indicated that ·OH produced during catalytic degradation process was the dominant active radical. Furthermore, Co, Cu and Ce species were involved in the generation of ·OH, which were responsible to the excellent performance of the catalyst/MW/HO system. The catalyst also showed good reusability and stability. Hence, the catalyst/MW/HO technology has potential application for the degradation of organic pollutants in wastewater.