Study On Preparation Of Electrolytic Manganese Slag Based Composite Adsorbent And Removal Of Hexavalent Chromium From Water

Electrolytic manganese Residue(EMR)is a kind of solid waste residue generated when Electrolytic manganese is produced in the Electrolytic manganese industry.Due to the increasing demand for electrolytic manganese and the decrease of manganese ore grade year by year,the total amount of electrolytic manganese slag in China is increasing day by day,but most enterprises will pile electrolytic manganese slag in the open air for a long time,which will not only cause the waste of land resources,but also pollute the surrounding environment.Therefore,it is of great practical significance to recycle and reduce electrolytic manganese slag.Chromium(Cr)ion is a kind of heavy metal ion with high toxicity and is one of the monitoring indexes of heavy metal pollution in water.With the rapid development of electroforging,printing and dyeing,leather making and other industries,a large number of industrial wastewater containing Cr(VI)is discharged into water bodies,resulting in increasingly serious water pollution problems.Therefore,the rapid and efficient removal of Cr(VI)from wastewater is a current research focus.The main components of electrolytic manganese slag(EMR)are silicon,manganese,calcium,iron,oxygen and sulfur.EMR contains active cations such as iron,manganese and aluminum,which can adsorb Cr(VI)to a certain extent.However,no reports have been reported on the adsorption of Cr(VI)by EMR.EMR is not suitable to be directly used as Cr(VI)adsorbent due to its complex composition,uneven distribution and small specific surface area.Therefore,the research on how to modify it can be used as a way of resource utilization of electrolytic manganese slag,as well as a necessary and effective direction,which not only contributes to the resource utilization and reduction of electrolytic manganese slag,but also uses waste treatment and waste treatment of hexavalent chromium wastewater for environmental pollution control,with dual effects.In this paper,electrolytic manganese slag was selected to carry out different organic modification to prepare two kinds of composite adsorbent,and the adsorption performance of the composite material on hexavalent chromium was explored and the mechanism was explored.The specific contents and conclusions are as follows:(1)Electrolytic Manganese slag based polypyrrole adsorbent(EMR-PPY)This chapter mainly after mixing with polypyrrole electrolytic manganese slag modified production become a kind of composite adsorbent,and applied to the removal of hexavalent chromium in water,by static adsorption equilibrium experiment study of the initial solution p H,contact time,initial concentration and reaction temperature experiment for its influence on the effect of adsorbent to remove hexavalent chromium,through the analysis of the characterization of desorption experiment and before and after the removal,The removal mechanism of hexavalent chromium by adsorbent was discussed.(2)Electrolytic Manganese slag-based chitosan Adsorbent(EMR-CS)This chapter will mainly electrolytic manganese residue blended with chitosan modified after making become a kind of composite adsorbent,and applied to the removal of hexavalent chromium in water,by static adsorption equilibrium experiment study of the initial solution p H,contact time,initial concentration and reaction temperature influence on the effect of experiment for the adsorption of hexavalent chromium,through the analysis of the characterization of desorption experiment and before and after the removal,The removal mechanism of hexavalent chromium by adsorbent was discussed.The conclusion is that when EMR-CS adsorption removes hexavalent chromium,the optimal solution p H is 2.0,EMR-CS adsorption is more in line with the quasi-second-order kinetic model.The adsorption capacity of EMR-CS to hexavalent chromium increases with the increase of the initial concentration of the solution and gradually reaches equilibrium.When the temperature is from 30℃ to 50℃,the adsorption capacity of emr-cs for hexavalent chromium is from 150mg/g to 160mg/g.The removal rate of 4 cycles was above 90%.There are three main adsorption mechanisms for hexavalent chromium by EMR-CS,namely electrostatic attraction,redox and complexation.