| Phenol is used widely in many fields of medicine, dyestuff, oil refining, chemical etc., because of its heavy toxicity, long-term drinking of water polluted by phenol can cause a series of problems in human health. Coking wastewater is complex, containing a large amount of phenol, cyanide, heterocyclic compounds and polycyclic aromatic hydrocarbons and other biodegradable substances, it is difficult to discharge to meet demand after biochemical treatment. Microwave induced catalytic oxidation is a new technology which is developing rapidly in recent years, it has a better effect on treating refractory wastewater. Therefore, the paper adopts this technology on studying two kinds of typical refractory wastewater of phenol wastewater and coking wastewater. Prepared three different forms of activated carbon as the carrier of catalyst Cu / GAC, Cu / AC, Cu/ACF by impregnation calcination method, the COD removal rate of aerobic effluent of coking wastewater as the evaluation index, the main factors affecting the performance of the catalysts were investigated, and the characterization of catalysts were analyzed. The influence of related factors on treatment of phenol wastewater and coking wastewater by microwave induced catalytic oxidation technology through the single factor experiment was examined, the degradation mechanism was analyzed and researched by following aspects: contrast experiment of different process, kinetics of fitting, the temperature rising process of activated carbon in microwave field,UV spectral scan of phenol. The conclusions can be drawn as following:(1) The best preparation conditions of Cu/GAC catalyst were determined: the impregnating solution concentration is 0.3mol/L, calcination temperature 300? and calcination time 3h; the best preparation conditions of Cu/AC catalyst were determined: the impregnating solution concentration is 0.2mol/L, calcination temperature 300 ? and calcination time 3h; the best preparation conditions of Cu/ACF catalyst were determined: the impregnating solution concentration is 0.2mol/L, calcination temperature 300? and calcination time 2h.Analyzing three kinds of catalyst by scanning electron microscopy, electron spectroscopy and X ray diffraction, we can find the active component of copper oxides are amorphous on the carrier, and copper oxides are in forms of CuO and Cu2 O, the weight percentage of copper for three catalyst Cu/GAC, Cu/AC, Cu/ACF are 0.10, 2.53, 1.36 respectively.(2) The rising process of granular activated carbon in the microwave field was studied, we can find that the granular activated carbon under microwave irradiation can heat up quickly. Under the condition of microwave time 10 min, microwave power 700 W, the surface temperature of activated carbon can reach 900?,it is proved that the activated carbon has a strong absorbing ability.(3) Cu / GAC as catalyst, H2O2 as oxidant, the treatment of phenol by microwave induced catalytic oxidation through the single factor experiment were investigated, for 100 mg / L phenol wastewater of 100 ml, the conclusion is showed as follows: the dosage of catalyst 3g / L, H2O2 dosage 2ml / L, pH = 4, microwave power 400 W, microwave time 4min, the phenol removal rate up to 99.96%, the COD removal rate up to 88.6%, the residual concentration of phenol is 0.04mg/L, the residual concentration of COD is 26.2mg/L. Phenol removal rate under different processes were discussed, find that the process of microwave+ catalyst + oxidation has synergistic effect, introduction of microwave and catalyst can promote H2O2 generate a large number of ·OH, the treatment efficiency of phenol is highest; Kinetics of fitting on phenol and COD removal rate during the reaction show that the both have first-order kinetics; Phenol effluent under different microwave time was scanning by UV spectral, we can find the degradation of phenol is completely.(4) Cu/GAC, Cu/AC, Cu/ACF as catalyst respectively, H2O2 as oxidant, the advanced treatment of coking wastewater by microwave induced catalytic oxidation were established. We can obtain for aerobic tank effluent of coking wastewater: Cu / GAC as catalyst, the optimum conditions are showed as follows: the dosage of catalyst 15 g / L, H2O2 dosage 10 ml / L, pH = 3, microwave power 400 W, microwave time 4min,the COD removal rate is 77.8%, the residual concentration of COD is 42.2mg/L; Cu / AC as catalyst, the optimum conditions are showed as follows: the dosage of catalyst 2g / L, H2O2 dosage 0.9ml / L, pH = 3, microwave power 400 W, microwave time 4min,the COD removal rate is 86.4%, the residual concentration of COD in wastewater is 25.8mg/L; Cu / ACF as catalyst, the optimum conditions are showed as follows: the dosage of catalyst 3g / L, H2O2 dosage 4ml / L, pH = 3, microwave power 400 W, microwave time 4min,the COD removal rate is 80.2%, the residual concentration of COD is 37.6mg/L.The COD removal rate under different processes were discussed, find that the process of microwave+ catalyst + oxidation has synergistic effect, it can improve the generation of ·OH in the reaction greatly, the treatment efficiency of coking wastewater up to maximum; Meanwhile, kinetics of fitting on COD removal rate during the reaction of three kinds of catalyst show that the all have first-order kinetics; The treatment of coking wastewater by microwave induced catalytic oxidation with some advantages: rapid reaction, high degree of mineralization, easy to realize automation management. The COD removal rate and colority of coking wastewater by treatment can reach direct emissions of The Emission Standards of Coking Chemical Industrial Pollutants(GB16171-2012). |
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