Study On Preparation Of Cork-based Activated Carbon Of Quercus Variabilis And Study On Its Dye Adsorption Properties

With the increasingly serious pollution of the earth’s environment,the government attaches great importance to the treatment of toxic and harmful chemicals with environmental persistence and bioaccumulation.Wastewater adsorption treatment is an effective method to purify wastewater pollutants.Using biomass materials in nature to explore the preparation of high-efficiency biomass activated carbon with good adsorption performance and recyclability is of great significance in the field of wastewater treatment.Quercus variabilis cork,as a natural porous biomass material stripped repeatedly,will produce some cork powder in the processing process.The honeycomb cell structure of these cork powder is not damaged,the carbon content is high and the ash content is low,which is suitable for the preparation of biomass activated carbon.In this study,Quercus variabilis cork powder was used as raw material to prepare activated carbon with excellent dye adsorption performance,explore the adsorption mechanism,endow the activated carbon with magnetic recovery characteristics,and prepare reusable magnetic cork activated carbon.The specific research work is as follows:1.Cork activated carbon with different pore structure and dye adsorption properties was prepared by sodium hydroxide,potassium hydroxide and phosphoric acid activation methods.The results showed that the specific surface area of activated carbon prepared by sodium hydroxide activation method was 2312.85 m2·g-1 under the conditions of pre carbonization temperature 300℃,activation temperature 800℃ and alkali carbon mass ratio 3:1.Under the conditions of pre carbonization temperature 550℃,activation temperature 750℃ and alkali carbon mass ratio 5:1,the specific surface area of activated carbon prepared by potassium hydroxide activation method is 3069.97 m·g-1.Compared with activated carbon prepared by phosphoric acid activation method,activated carbon prepared by potassium hydroxide and sodium hydroxide activation method has more developed pores,and the pore size is concentrated at 2～4 nm(V2～4nm=0.6 cm3·g-1),which has better adsorption performance for liquid dye molecules;2.Rhodamine B(RhB)represented by cationic dye and methyl orange(MO)represented by anionic dye were used as target pollutants to explore the adsorption behavior of cork activated carbon to dyes.The results show that the adsorption capacity of cork activated carbon for RhB is higher than that of MO,which is more suitable for RhB under alkaline conditions and MO under acidic conditions.With the increase of adsorption temperature,cork activated carbon is more favorable for the adsorption of RhB than MO.The adsorption behavior conforms to Langmuir isotherm model and quasi second-order kinetic model.Through Langmuir model fitting calculation,the maximum theoretical adsorption values of RhB and MO on cork activated carbon are 2712.03 mg·g-1 and 925.93 mg·g-1 respectively.The adsorption mechanism is related to the pore structure and surface charge properties of activated carbon;3.Magnesium iron bimetallic magnetic nanoparticles were loaded on the surface of activated carbon by hydrothermal solvent method to prepare magnetic cork activated carbon with good magnetic recycling ability.Characterized by SEM-EDS,FTIR,XRD,BET and VSM,Magnesium iron bimetallic magnetic nanoparticles are evenly distributed on the surface of activated carbon and occupy some pores.The specific surface area is 1886.65 m2·g-1 and the saturation magnetization(Ms)is 15.09 emu·g-1;Rapid solid-liquid separation can be realized by magnetic field.After three adsorption desorption cycles,the adsorption capacity of magnetic cork activated carbon for RhB than MO can still reach 1122.31 mg·g-1 and 302.49 mg·g1.