Microwave Modified Bentonite Studied The Adsorption Process Of Wastewater Containing Lead

Since Pb2+-containing wastewater is harmful to environment and threat our health,in this paper,used source widely,inexpensive,strong adsorption Bentonite to adsorb it. The writer mainly inspected the best making condition of bentonite by microwave modified,the best adsorption conditions towards Pb2+-containing wastewater, finally investigated adsorption mechanism.The bentonite used in the experiments was the Na-bentonite produced in Nanning,Guangxi. The Na-bentonite was not good regarding the adsorption performance of Pb2+.In order to make the bentonite suitable for the treatment of Pb2+-containing wastewater,we carried out the bentonite modification research. The experiments resulted in two methods by microwave and achieved the best making conditions. Microwave-bentonite : middle power , heating 8min. Organic-microwave-bentonite:modified reagent dosage was 3g/5g,solid-fluid ratio was10:5 , alcohol volume concentration was 75% , radiation intension was Q>50W/g , radiation time was 1.5min. In view of organic-microwave-bentonite preparation condition more complex,carried on the orthogonal optimization experiment to it, the test results demonstrated that modified reagent dosage was biggest to the modified effect influence, next for microwave exposure time and alcohol volume concentration.The adsorption experiments using the modified bentonite were carried out and the best adsorption conditions of Pb2+ was given. Na-bentonite:solid-fluid ratio was 12g/L, T=40℃,adsorption time was 50min, pH=6, removing rate achieved 72.9%. Microwave-bentonit:solid-fluid ratio was 12g/L,T=50℃,adsorption time was 20min, pH=6,removing rate achieved 86.7%. Organic-microwave-bentonite: solid-fluid ratio was 8g/L,T=50℃,adsorption time was10min, pH=6,removing rate achieved 99.5%.In this experiment,the modified bentonite was used to treat the actual acidity Pb2+-containing wastewater, indicated the adsorption effect of organic-microwave-bentonite was best,when pH=8, the solid fluid ratio was 5g/L,removing rate achieved 99.6%. The paper used the advanced testing techniques such as SEM,IR and XRD to carry out the characterization on the modified bentonite,and studied the adsorption mechanism of Pb2+ on it. Regarding the isothermal experiments of organic-microwave-bentonite,it indicated that it follows the Langmuir equation and the Freundlich equation.The above findings have certain theoretical and practical significances for using the adsorption performance of bentonite to treat wastewater,especially Pb2+-containing wastewater. Simultaneously a new way to enhance the application value of bentonite in our country has been developed.