Preparation Of Sludge Biochar And Its Decolorization Of Dye

Adsorption method and advanced oxidation process are always used in treating dye wastewater.But traditional adsorption method which is based on activated carbon as adsorbent,the cost is higher,and after the adsorption process,the activated carbon need to be actived under high temperature.Fenton method is relatively commonly used as advanced oxidation process.But the process has obvious flaw which produce so much iron sludge and the Fe³⁺will influence colority of the water.In this paper,aiming at problems that exist in traditional adsorption process and Fenton process,the biochar,biochar/Co adsorbent and biochar/Co/Fe catalyst were prepared by hydrothermal method.The samples obtained were characterized by X-ray diffraction?XRD?,X-ray photoelectron spectroscopy?XPS?,electron microscopy?SEM?,nitrogen adsorption-desorption?BET?,the hysteresis loop?VSM?,thermal gravimetric analysis?TGA?,Fourier transformed infrared?FT-IR?.The adsorption and catalytic degradation properties of materials were investigated using Congo red.Through the research,it can draw the following conclusions from this experiment: The biochar were prepared by hydrothermal reaction.Through signal factor experiments to research the effect on removal rate of Congo red which include hydrothermal temperature,residence time,the hydrothermal p H,the fil ing rate of sludge.Through the experiment,the most optimum hydrothermal conditions were : the hydrothermal temperature was 180 ?;the residence time was 3h;the hydrothermal p H was 9;the fil ing rate of sludge was 1g.Through characterization analysis :the sludge was carbonized,the biochar performed porous morphology,and the specific surface area increased,the thermal stability improved,the oxygen functional groups decreased which effect the adsorption properties of the biochar.In order to improve the adsorption properties of the biochar,the biochar/Co composite materials with different amounts of Co were prepared.The results showed that when the concentration of Co was 8 g/L,and the specific surface area increased from 42.651 m²/g to 71.579 m²/g,the removal rate was 97.3% which increased by 54.3% compared with the blank test.Furthermore,the influence factor which include temperature,p H,water quality were studied.Through the research,it can be draw: the adsorption of Congo red process belonged to the exothermic reaction,with the temperature increasing,the removal rate will decrease.Acidic environment had small effect on the removal rate,but under the alkaline environment,the removal rate will decrease rapidly.The main reason is that the OH^-will take up active site of adsorbent.In order to research the effect of actual water on the removal rate,the tap water was chosen instead of distilled water,the result showed that the removal rate decreased because of the existence of organic material and ion,the rate was just 4.38%.The adsorption reaction to CR followed pseudo-second order kinetic model,and belonged to the chemical adsorption.Additionally,the isothermal adsorption curve of adsorbent fitted Langmuir type and attributed to monolayer adsorption.Based on the above research,the biochar/Co/Fe composite materials were prepared to degrade the high concentration CR.Through the single factor experiment,the influence factors include iron ion doping amount,material dosing quantity,H₂O₂ dosing quantity,p H were researched.The composite material doped with 4 mmol Fe³⁺was chosen to research the most optimum conditions,the result showed that degradation rate was 100% when the material dosing quantity was 0.1g/L,H₂O₂ dosing quantity was 0.75 m L/L,p H was 3.SEM images showed that carbon microspheres appeared when the Fe³⁺added.VSM showed that saturated magnetic intensity of the composite material is 17.749 emu/g which is stronger than biochar/Co.XRD showed the emergence of Fe₃O₄ when the Fe³⁺added which was in accordance with VSM.XPS showed C,Co,Fe combined with each other wel.According to the mechanism of degradation of Congo red in Fenton-like process,the composite material has the adsoption and Fenton reaction.