Study on the adsorption performance of Pb2+in water by Birnessite-type manganese dioxide nanoflowers
The pollution of heavy metals in water has caused an important impact on human production and life.In this paper,Birnessite type manganese dioxide nanomaterials were used as new adsorbents to study the ad-sorption properties of Pb2+in water.Firstly,the Birnessite MnO2 nanoflowers with the size from 200 nm to 900 nm were prepared by liquid phase synthesis method,and the adsorptive property of the obtained samples was studied by Pb2+adsorption experiments.The effects of pH value,ionic strength,material size,adsorption time and initial concentration of Pb2+were investigated.The adsorption mechanism of Pb2+was studied with the fit-ting data of kinetic model and isothermal adsorption curve model.The experimental results showed that the pre-pared Birnessite MnO2 nanoflowers had excellent adsorption properties for Pb2+in water with the pH value 5-9,and the maximum adsorption capacity was up to 300 mg·g-1.The Birnessite MnO2 nanoflowers with the smal-ler size had the larger specific surface area,which caused the better adsorption performance.The Birnessite MnO2 nanoflowers still had about 80％adsorption capacity when the Pb2+adsorption experiment carried out in high ionic strength solution.The fitting data of adsorption kinetics and isothermal adsorption curve show that the adsorption process of Pb2+by Birnessite MnO2 nanoflowers is mainly the process of uniform coverage by single molecular layer with chemisorption process.
manganese dioxidenanoflowerheavy metal adsorptionadsorption kineticsisothermal adsorption curve
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