The Spent Catalyst Heat Treatment Products Of Adsorption Of Organic Wastewater

According to the property and characteristic of spent catalyst, addressing the problems of the preparation process of photocatalyst/activated carbon composite material, and analyzing the preparation and application status quo of activated carbon. A novel process of manufacturing ZnO/AC composite material and activated carbon from spent catalyst by heating directly was put forward. Under different temperature, the reaction mechanism of spent catalyst was investigated through the examination of adsorption capability and the analysis of zinc quantity contained and pore structure. Furthermore, the adsorption of methyl orange or phenol from aqueous solution by activated carbon and ZnO/AC composite material, the activated carbon microwave regeneration and the ZnO/AC composite material photocatalytic regeneration were studied.The iodine number and methylene blue adsorption of samples were determined separately by National Standards GB/T12496.8-1999 and GB/T12496.10-1999, then, the components and microstructures of samples were characterized by analyzed zinc quantity contained, pore structure, X-ray analysis and scanning electron microscopy. The results showed that, with the heating temperature increasing, the iodine number, the methylene blue adsorption, the surface area and the total pore volume were first increased and then decreased;the zinc quantity contained was decreased all the time. The samples contained zinc quantity were more than 6.300% under the heating temperature from 673K to 1173K, which were proved as ZnO/AC composite material, and the samples contained zinc quantity were less than 0.0094% when the heating temperature higher than 1273K, which were proved as activated carbon. It can be found that the samples contained hexagonal zinc oxide with the heating temperature during 673K to 1173K from the XRD, but not showed diffraction peaks of zinc oxide under the heating temperature from 1273K to 1473K. According to SEM analysis, at the 1073K, many ZnO particles which distributed uniformly on the surface and wall of pore of the activated carbon were loaded on the samples, but the number of ZnO particles was few at 1273K.A systematic study was carried out for disposal of methyl orange or phenol from aqueous solution by the activated carbon or ZnO/AC composite material which was obtained under 1273K and 1073K, respectively. The effects of shaking, dosage, initial concentration and solution temperature on the methyl orange or phenol removal ratio were studied, and obtained the optimal process parameters. The thermodynamic parameters of adsorption were calculated by Van't Hoff equation, and analyzed the equilibrium data by Langmuir and Freundlich isotherms at different temperatures. The experimental data were analyzed by the pseudo second order kinetics model, obtaining the initial sorption rate and rate constants. The results showed that, the pseudo second order kinetics model fit the experimental data well. Under the experimental conditions, it was found that the controlling step of adsorption methyl orange or phenol from aqueous solution by activated carbon or ZnO/AC composite material were all film diffusion controlling processes.To methyl orange and phenol as the goal of pollutants, it studied on the microwave regeneration of activated carbon which was obtained under 1273K, and on the photocatalytic regeneration of ZnO/AC composite material which was obtained under 1073K. It was found that, the microwave regeneration of activated carbon required for the shorter hours, better regeneration, but brought environmental pollution, loss of raw materials and other issues; the photocatalytic regeneration ratio of ZnO/AC composite material was relatively low, regeneration time was long, but ZnO can renew the adsorption capability of activated carbon by light. The photocatalytic regeneration can brought that the cost savings, the material loss and the environmental pollution were all decreased. So, it is great significance for the field of energy, resource and environmental. In a word, the ZnO/AC composite material and activated carbon obtained directly by heating plant waste(spent catalyst). This process has many advantages, such as reduction of environmental pollution, utilization effective of secondary resources, at the same time, shortening of preparation process of photocatalyst/activated carbon composite material, reduction of preparation cost. The samples which were used for adsorbing organic wastewater are able to save the cost of wastewater treatment, in order to reach the purpose of waste control by waste, and widening of raw materials for wastewater treatment. Furthermore, activated carbon and ZnO/AC composite material were regenerated by microwave heating and photocatalysis, respectively, which have great significance for energy-saving and ejection-decreasing and circulation of natural resource.