Studies On The Extraction Of Cellulose From Pomelo Peel,Chemica Modified With Succinic Anhydridelly And Its Absorption Properties For Heavy Metals

With the rapid economic development, a large number of wastewater increased the accumulation of heavy metal in the soil and water resources, so heavy metals pollution is becoming a increasingly serious problem. Heavy metals are easily bioaccumulated through the food chain, so it has a serious threat to human health and other living organisms. Therefore, how to remove heavy metals from wastewater efficiently has become a human concern.Adopting the chemical separation techniques, single factor experiments and orthogonal experiments, pomelo peel was used as a raw material to extract the cellulose in this artiele. The modified pomelo peel cellulose (Cell 5 and Cell 6) is prepared in laboratory with succinic anhydridelly(SA) and is characterized by means of modern instruments. And the absorbent activity to heavy metals such as Cu2+ and Pb2+ by modified SA was studied in terms of temperature influence,pH value,adsorption kinetics, isotherm adsorption and resolution experiment.The results were as follows:1,The effects of NaOH concentration, H2O2 concentration, decolouration time and decolouration temperature were studied in single factor experiments.The orthogonal experiments were accomplished on the base of the single factor experiments.The results showed that the optimum condition of cellulose extraction were as follows:NaOH concentration was 6%, H2O2 concentration was 10%, decolouration time was 30 minutes while the decolouration temperature was 30℃.The purity of the sample under the optimum condition was 67.7%, The product was milky white powder with some grapefruit scent.2,The modified pomelo peel cellulose is prepared with succinic anhydridelly(SA),catalyst of pyridine and is characterized by means of FTIR,XRD and SEM. The results showed that the modified pomelo peel cellulose molecules introduced carboxyl and hydroxyl functional group.3,The effects of the adsorption temperature and pH value on the removal of heavy metal ion by modified pomelo peel cellulose were studied. The optimization adsorption conditions are metal ions concentration 200ppm, adsorbent amount 0.02g, pH value 4.5-5.5,temperature 25-30℃and adsorption system 20mL.4,The effects of the adsorption kinetics and isotherm adsorption on the removal of heavy metal ion by Cell 5 and Cell 6 were thoroughly studied. As a typical example, experimental data of heavy metal ions were exploited for kinetic and isothermal evaluations.lt was found that adsorption is a fast, stable process, reaching adsorption equilibrium about 1h and the sorption kinetics of Cu2+ and Pb2+ on Cell 5 and Cell 6 obeyed pseudo-second-order sorption kinetics. Sorption equilibrium studies demonstrated that the biosorption followed Langmuir isotherm model.The maximum adsorption capacity of Cell 5 and Cell 6 were 86.21mg/g and 100mg/g for Cu2+, respectively. For Pb2+, the maximum adsorption capacity of Cell 5 and Cell 6 were 142.86mg/g and 181.82mg/g, respectively. The modified mercerized Cell 6 showed a higher adsorption capacity for Cu2+ and Pb2+ than modified non-mercerized Cell 5.5,Desorption of Cu2+ and Pb2+ from Cell 6 with 0.1mol/L HCl resulted in 90.8% and 84.1% recovery of these metals, respectively.6,The adsorption mechanism may be partly a result of the ion exchange or complexation, the other may be physical adsorption.