Study On The Adsorption Performance Of Attapulgite And Magnetic Materials For Environmental Pollutants

With the development of social industrialization,the demand for chemicals in human life is increasing,thus leading to more and more serious water environmental pollution.In the discharge of sewage,there are many complex components,such as heavy metals,organic dyes,and so on.Due to the bright color,difficult degradation,structure stability,organic dyes are considered to be the first pollutant in the water body,which is immeasurable for the damage of the environment,soil and human health.Therefore,the treatment of dye wastewater has been a highly concerned problem.In recent years,a large number of treatment technologies such as adsorption,photocatalysis and electrochemical methods have been used in wastewater treatment.Of which the adsorption method has been studied extensively because of its potential advantages,such as simple operation,high treatment efficiency,low cost and recycling.Based on this,in this paper,attapulgite was modified and two different magnetic adsorbents were synthesized by using the different methods,and their adsorption properties for different dyes in water were investigated.The main research work is as follows:1.Attapulgite（ATP）as raw material was activated under different temperatures（400℃,500 ℃,600 ℃,800 ℃）and different Na OH concentrations(1 mol·L^-1,3 mol·L^-1,5 mol·L^-1),which was used to remove methyl violet（MV）dye in water.The morphology,structure and composition of the activated ATP materials were measured and compared using SEM,FT-IR and other characterization methods.Under the same experimental conditions,the adsorption performance of different activated ATP materials to MV dyes was comparatively studied,and the best activation condition was finally obtained through comparative analysis.The results showed that 3 M-ATP and 400℃-ATP were the best modification conditions,and the maximum adsorption capacity of MV was 147.28 mg·g^-1and 142.86 mg·g^-1,respectively.2.The magnetic biochar material（M-CS）was successfully prepared from waste sweet sorghum by a simple soaking-high temperature calcination method.The morphology,composition and magnetic properties of M-CS material were characterized.The M-CS material was used as the adsorbent to remove the target dye methylene blue（MB）,and the influencing factors were optimized.In addition,the adsorption behavior of MB dye on M-CS material,as well as recycling performance of M-CS material were investigated.The experimental results showed that the adsorption process of M-CS material on MB is in accordance with pseudo-second-order kinetics and Langmuir isothermal adsorption model,and the maximum adsorption capacity is 41.4 mg·g^-1.3.Chitosan and Fe₃O₄were used as raw materials to successfully synthesize Chitosan@Fe₃O₄by a simple,green and friendly solvent-free ball milling method.The surface morphology,phase composition,structure and magnetic properties of the Chitosan@Fe₃O₄material were characterizd using SEM,FT-IR,XRD,VSM methods.The prepared material was used as an adsorbent to remove the target congo red dye（CR）.The effect of experimental factors such as solution p H and contact time on the adsorption performance were studied and optimized.The adsorption behavior of Chitosan@Fe₃O₄material for CR dye was investigated,and the adsorption mechanism,recycling performance of the materials were discussed.The final results showed that under the optimal conditions(p H=4,adsorbent dosage of 0.45g·L^-1),the maximum adsorption capacity of the material for Congo red was 751.9 mg·g^-1.