Adsorption properties of bentonite-modified Microcystis-based biochar to Cr(Ⅵ)
Aiming at the problems such as difficult treatment of highly toxic chromium-containing wastewater and poor efficiency of resource utilization of algae,bentonite-modified Microcystis-based biochar(BMC)was to be prepared in this study.The properties of Microcystis-based biochar before and after modified by bentonite were characterized by scanning electron microscope,X-ray diffraction and specific surface area analysis.The effects of initial pH and biochar dosage on the Cr(Ⅵ)adsorption of Microcystis-based biochar be-fore and after modified were studied,and the adsorption processes were fitted by kinetic and isothermal models.The results show that,the surface functional groups and cation exchange capacity of Microcystis-based biochar increased significantly after modified by bentonite,and the adsorp-tion process of Cr(Ⅵ)by the Microcystis-based biochar before and after modified were all characterized by the quasi-sec-ondary kinetic model and Langmuir isothermal model.Under the experimental conditions of pH=2 and dosage of 2 g/L,the saturated adsorption capacity of Cr(Ⅵ)by modified Microcystis-based biochar reached 10.87 mg/g,which was 3.94 times of Microcystis-based biochar(MC)before modification.The adsorption of Cr(Ⅵ)was significantly promoted by the modified Microcystis-based biochar.Electrostatic adsorption and redox were the key mechanisms for Cr(Ⅵ)removal by Microcystis-based biochar.The research results can provide new methods for the treatment of chromium-containing wastewater and new ideas for resource utilization of algae blooms.
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维普
