Study On Preparation And Water Treatment Performance Of Functional Magnetic Biomass-Based Activated Carbon

Activated carbon not only has a high specific surface area,rich porous structure and oxygen-containing functional groups,but also has the advantages of a wide range of precursors and low cost.It is known as the most widely used carbon material,especially in the fields of environmental treatment and water restoration.In this thesis,three modified composites were prepared using garlic straw as the activated carbon precursor and Fe₃O₄ to provide superparamagnetic properties for rapid recovery from water.Molybdenum disulfide functionalized magnetic biomass activated carbon,magnesium and aluminum bimetallic hydroxide functionalized magnetic biomass activated carbon,and polyaniline magnetic biomass activated carbon were prepared.The three materials were characterized by physical characterization such as scanning electron microscopy,transmission electron microscopy,infrared spectroscopy,X-ray diffraction,nitrogen adsorption and desorption and vibrating sample magnetometer,and their adsorption properties on wastewater pollutants were also investigated.The details of the study are as follows:（1）Biomass-based activated carbon（BAC）was firstly prepared by chemical activation,then magnetic biomass activated carbon（m BAC）was prepared by co-precipitation method,and later molybdenum disulfide-functionalized magnetic biomass activated carbon（Mo S₂-m BAC）was prepared by hydrothermal method.Mo S₂-m BAC showed excellent adsorption of tetracycline（TC）and crystalline violet（CV）.The effects of adsorbent dosage,initial pH of solution,contact time,initial concentration of pollutants and temperature on the adsorption process were investigated.In the kinetic study,the proposed secondary kinetic model could better describe the adsorption processes on tetracycline and crystalline violet.In the isothermal adsorption model,the adsorption isotherms of crystalline violet and tetracycline conformed to the Langmuir isotherm model,and the maximum adsorption amounts（q_m）of Mo S₂-m BAC for TC and CV were 286.53 mg/g and 568.18 mg/g,respectively.Thermodynamic studies showed that the adsorption of TC and CV by Mo S₂-m BAC increased with the increase of temperature,which was a spontaneous heat absorption process.In the reproducibility study,the removal rates of tetracycline and crystalline violet remained 76%and 84.3%after five cycles.（2）Based on the magnetic biomass activated carbon already prepared in the first part,polyaniline functionalized magnetic biomass activated carbon（PANI-m BAC）was prepared by chemical oxidation.PANI-m BAC was used for the adsorption experiments on the dye methyl orange（MO）.The effects of adsorbent dosage,initial pH of solution,contact time,initial concentration of pollutants and temperature on the whole adsorption process were firstly investigated.Then in the subsequent investigation,it was found that the quasi-secondary kinetic model could better describe the adsorption process of methyl orange in the kinetic study.In the isothermal adsorption model,the Langmuir isotherm model was more consistent with the adsorption isotherm of methyl orange and the maximum adsorption amount（q_m）of PANI-m BAC on MO was 271.00 mg/g.While the thermodynamic study showed that the adsorption of MO by PANI-m BAC was a spontaneous heat absorption process that increased with the increase of temperature.In the reproducibility study,the removal of MO was still 83.44%after five cycles.（3）On the basis of magnetic biomass activated carbon prepared in the first part,magnesium-aluminum bimetallic hydroxide functionalized magnetic biomass activated carbon（MA-m BAC）was prepared by nucleation crystallization isolation method.MA-m BAC was used for the removal of the dye methylene blue（MB）.The effects of adsorbent dosage,initial pH of solution,contact time,initial concentration of contaminants and temperature on the whole adsorption process were firstly investigated.Then,in the later investigation,it was found that the adsorption process of methylene blue was more consistent with the proposed secondary kinetic model in the kinetic study.In the isothermal adsorption model,the adsorption isotherm of methylene blue conformed to the Langmuir isotherm model and the maximum adsorption amount（q_m）of MA-m BAC on MB was 436.80 mg/g.And the thermodynamic study showed that the adsorption of MA-m BAC on MB was a spontaneous heat absorption process that increased with temperature.In the reproducibility study,the removal of methylene blue was still up to 74.76%after five cycles.