Study On Preparation Of MnO₂/γ-Al₂O₃and Adsorption And Degradation Of Glyphosate In Microwave Coupled With Ultraviolet Process

Glyphosate is a kind of refractory wastewater, which is high of salt and acidity,and contains a variety of substance that is difficult to biodegrade. If dischargedinto water, the environment and the ecosystem would be damaged greatly.Glyphosate wastewater treatment issues has restricted the development ofenterprises recently. This article construct a method of disposal of organic matter,which is adsorption-degradation-regeneration process, the MnO2/γ-Al2O3wasmade through mixing and calcinations, which was used to adsorb the glyphosate,and then the adsorbed glyphosate was placed in a microwave coupled with UVsystem for degradation and regeneration. This process not only solve the problem ofwaste water treatment of glyphosate, also provides a feasible method of glyphosatefinal disposal and MnO2/γ-Al2O3regeneration.The optimal prepared conditions of MnO2/γ-Al2O3were studied, factors ofpreparation MnO2/γ-Al2O3were optimized by heating and adsorption effect. Theoptimum conditions for preparation MnO2/γ-Al2O3was30%(mass fraction) ofMnO2and calcined at500℃for4h. Testing MnO2/γ-Al2O3of SEM, BET, XRD,compressive strength analysis, specific surface area of MnO2/γ-Al2O3is191.2055m2/g, with the average pore diameter of10.8935nm, the total pore volume of0.5971cm3/g, a typical mesoporous structure. MnO2/γ-Al2O3does not generatemicrowave inert material Mn3O4in the microwave field, so you can achievemultiple reusable MnO2/γ-Al2O3. The compressive strength of MnO2/γ-Al2O3is77.3N/tablets.The optimum experimental conditions for glyphosate adsorption were given.The maximum adsorption amount of MnO2/γ-Al2O3for glyphosate was83mg/g atnormal temperature. Temperature has little influence on the adsorption capacity, theadsorption capacity decreased slightly with elevated temperature. pH has a greatinfluence on the adsorption capacity with, the adsorption capacity was significantlyreduced when pH increases. MnO2/γ-Al2O3adsorption of glyphosate reachadsorption equilibrium in6hours, adsorption capacity at0.5h can reach40mg/g.The type of adsorption process is physical adsorption. After adsorption of MnO2/γ-Al2O3, glyphosate concentration can meet emission standards.The optimized parameters of microwave coupled with UV process were500watts of power at a ventilatory volume of0.06m3/h for20min. The regenerationrate of MnO2/γ-Al2O3reached85%under the optimum operating conditions, and MnO2/γ-Al2O3can be recycled many times. Glyphosate eventually degraded tocarbon dioxide, nitrogen oxides, phosphate and water, and the rate of mineralizationreached65%.