| Camellia shell resource is abundant in China,but it has not been utilized effectively,most of which is discarded or burned.The camellia shell contains about 30% of cellulose,which has great economic benefit as an excellent material for synthesizing cellulose adsorbent.Cellulose adsorbent has the advantages of wide raw material source,low production cost and high adsorption efficiency,which can effectively solve the problem of heavy metal pollution.This paper studied the extraction and purification process of cellulose from Camellia shell,synthesized cellulose xanthate adsorbent via modification of cellulose and investigated the adsorption properties of adsorbent to Cu2+.The main research contents were as follows:(1)Using dilute nitric acid to remove lignin,hemicellulose and other components in the camellia shell,to achieve the purpose of extracting cellulose.The effects of the concentration of nitric acid,the ratio of solid-liquid,the temperature of acid solution,the time of acid solution and the number of acid hydrolysis on the acid hydrolysis rate of camellia shell were investigated.The results showed that optimum technological conditions: The acid hydrolysis temperature was 75 ?,the acid hydrolysis time was 90 min,the ratio of solid-liquid was 1:10,the concentration of nitrate was 12%,the number of acid hydrolysis was one time,under these conditions,the acid hydrolysis rate was 61.42%.The crude cellulose samples were detected by using FT-IR,SEM,XRD and other detection methods.The results showed that the aromatic compounds containing benzene ring structure did not exist in the sample,the lignin removal layer was damaged.(2)Na OH and H2O2 were used to purify the crude cellulose.The effects of H2O2 concentration,liquid-solid ratio,Na OH concentration,reaction temperature,reaction time on the purity of cellulose were investigated,The optimal purification process conditions: the concentration of H2O2 was 5%,the ratio of liquid to solid was 26:1,the concentration of Na OH was 2%,the reaction temperature was 40 ? and the reaction time was 120 min.Under these conditions,the purity of cellulose could reach 94.78%.The products were characterized by FT-IR,SEM,XRD and TG.The results showed that the purified product was in agreement with the structure of cellulose.(3)Under the action of Na OH,the cellulose xanthate was synthesized with the purified cellulose as raw material and CS2 as modifier though sterification reaction.The synthetic products were characterized by FT-IR and SEM.The results showed that cellulose molecules were introduced successfully into xanthate groups,and the product surface was rough,there were a lot of pore structure.The reaction activity of cellulose and CS2 was analyzed by the frontier orbital theory,and the reaction mechanism was simulated from the point of view of quantum chemistry(4)With cellulose xanthate as adsorbent,the effects of adsorbent dosage,initial concentration,solution p H,adsorption temperature and adsorption time on the removal rate of Cu2+ and the adsorption capacity on the adsorption process were studied.The optimum adsorption conditions: the adsorbent dosage was 0.10 g,the initial concentration of copper ion was 50 mg/L,the solution p H was 3,and the adsorption time was 30 min.Under these conditions,the removal rate reached 98.88%,and the adsorption capacity was 24.72 mg/g.The results of adsorption kinetics and isothermal adsorption showed that the adsorption process was in accordance with the pseudo-second-order kinetic model and the Langmuir isotherm model,the maximum adsorption capacity was 91.24 mg/g. |
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