Modification Of Cellulose-based Adsorbant And Its Performance On The Removal Of Arsenic Ions

Cellulose is a naturally degradable polymer material and is an environmentally friendly material without secondary pollution.In this paper,three adsorbents of cellulose-loaded zero-valent iron,cellulose-supported iron-bismuth double-oxide and cellulose-supported iron-manganese double-metal oxide were prepared by using wood chip cellulose as the substrate.The adsorption properties of three materials for arsenic-containing wastewater were studied.At the same time,the characteristics of three kinds of adsorbent materials were characterized: scanning electron microscopy,SEM-EDX before and after synthesis of modified materials,FTIR and SEM-EDX mapping to prove the success of the synthesis reaction.The C-ZVI adsorbent was prepared by liquid-phase reduction method using wood chip cellulose as the matrix material.The C-ZVI was characterized by FTIR and scanning electron microscopy(SEM).The adsorbent was successfully prepared.The adsorption properties of C-ZVI on arsenic ions(As)in water were investigated.In addition,the optimal adsorption conditions,adsorption kinetics and isothermal adsorption model of the adsorbent were discussed.The results show that when the arsenic ion concentration is lower than 100 mg/L,the adsorption efficiency can reach more than 90 %.When the pH of the solution is 3-7,the dosage of the adsorbent is 2 g/L,the reaction temperature is 25 °C,and the initial concentration of As is 100 mg/L,the adsorption capacity of C-ZVI to As is as high as 45.69 mg/g.Fitting the adsorption data to determine the adsorption of arsenic ions by C-ZVI accords with the Freundlich isotherm adsorption model,indicating that the adsorption is dominated by multi-layer adsorption.The adsorption kinetics data of C-ZVI showed that the whole adsorption process followed the quasi-secondary adsorption kinetics model,indicating that it was dominated by chemical adsorption.Since both iron oxide and cerium oxide have strong adsorption properties,the supported iron-bismuth bimetallic oxide cellulose was prepared by co-precipitation method,and its adsorption performance was studied.The adsorption performance of the prepared iron-bearing bimetallic oxide cellulose on arsenic ions was investigated.The optimal adsorption conditions were determined by adsorption test: pH = 2-10,the adsorption takes about 60 min to reach equilibrium,and the lower the of initial As ion,the higher the adsorption efficiency,and the maximum adsorption capacity can reach 32 mg/g.By fitting the adsorption kinetic data of As ion,the adsorption of As ion by the supported iron-bismuth bimetallic oxide cellulose accords with the pseudo-second-order kinetic model,indicating that the adsorption mechanism is mainly chemical adsorption.By fitting the data of the isothermal adsorption model,it is proved that the adsorption of As ions by the supported iron-bismuth bimetallic oxide cellulose conforms to the Freundlich isotherm adsorption model,indicating that the reaction is dominated by multi-layer adsorption.Manganese dioxide has an oxidizing effect that oxidizes trivalent arsenic ions into pentavalent arsenic ions that are more easily removed.In this experiment,the supported iron-manganese bimetal oxide cellulose was successfully prepared by co-precipitation method.The experimental results show that the lower the initial As ion concentration,the higher the adsorption efficiency with a pH of 3-7 and the adsorption time is 60 min.The maximum adsorption capacity can reach 21.42 mg/g.By fitting the adsorption kinetic data of As ions,the adsorption of As ions by supported iron-manganese bimetal oxide cellulose conforms to the pseudo-second-order kinetic model,and the fitting degree is up to 0.9999,indicating that the adsorption mechanism is mainly chemical adsorption.The adsorption of the adsorbent on the isothermal adsorption model data was investigated.The adsorption of arsenic ions by the supported iron-bismuth bimetallic oxide cellulose was more consistent with the Langmuir isotherm adsorption model,indicating that the adsorption was dominated by monolayer adsorption.