A Study On The Electro-catalytic Degradation Of Phenolic Waste Water By Clinoptilolite-loaded Metallic Oxides

Phenol is a kind of toxic substance, which extensively exists in industrial waste water and is difficult to be removed, inflicting huge harm to organisms and the environment. In order to remove the phenol pollutants more effectively, experiments were conducted in this study using phenol as simulate waste water in self-regulation reaction vessel. Adopting the impregnated sintering method, a supported catalyst with clinoptilolite as its carrier was made. Further, employing the electrochemical oxidation technology, the author observed the phenol and TOC degradation efficiency of one-and multi-component metallic oxide supported catalyst. Meanwhile, the surface morphology and the inner crystal structure of the catalyst were analyzed via scanning electron microscopy (SEM) and X-ray diffraction (XRD), and the metallic oxides loaded catalyst layer was qualitatively analyzed. In addition, the effects of catalyst dosage, current density, pH value, concentration of supporting electrolyte, plate spacing and sintering temperature of catalyst on the phenol degradation efficiencywere observed. The reusability of the catalyst was testified and the dynamic analysis was performed.The result shows that, several metallic oxides loaded catalysts have efficient catalytic effect on the degradation process of phenol except Zn. Using Fe, Sn, Ce as the catalyst layer, the phenol removal rate reached71.8%,66.0%and63.4%respectively, and the total organic carbon (TOC) removal efficiency reached35.0%,37.5%and41.0%. Multi-component metallic oxides loaded catalyst has far higher catalytic efficiency. When the molar ratio of the Fe, Sn, Ce in the impregnating solution was6:3:2, the phenol removal rate and TOC removal efficiency of the catalyst reached83.2%and70.6%respectively. The best catalyst preparing temperature is550℃.The XRD displayed obvious Fe, Sn, Ce oxide diffraction peaks, indicating that a load oxide layer was formed on the surface of the catalyst. The SEM photo shows the catalyst layer was uniform and compact, reflecting good morphology, in accordance with the standard of high efficiency catalyst.The phenol degradation efficiency was maximized when the initial phenol concentration was100mg/L, the multicomponent Fn-Sn-Ce catalyst dosage was60g/L, the pH value was5.0, the current density was42.6mA/cm2, the concentration of supporting electrolyte was0.5mol/L, and the plate spacing was6cm. This degradation process fits the first-order kinetics and its reaction rate constant is0.04453min-1. Furthermore, the catalyst retained good catalytic activity after being utilized6times, with the phenol removal rate and total organic carbon (TOC) removal efficiency still reaching80.31%and75.56%respectively. The phenol degradation mechanism of clinoptilolite-loaded multi-metallic oxides electro-catalysis may operate in two ways, namely, producing·OH and attacking the benzene ring, and the direct oxidative degradation by three-dimension electrodes system made of positive and negative plates and particle electrode.