STUDY ON ADSORPTION EFFICIENCY AND KINETICS OF METHYLENE BLUE BY POLYMERIC MATERIALS OF STARCH-ACRYLATE-PULLULAN POLYSACCHARIDES

Using potato starch as the basic skeleton,small molecule acrylic acid (AA),structurally elastic straight pullulan (PULL) as raw material in the environment of potassium persulfate as initiator,N,N'-methylenebisacrylamide as cross-linking agent,the starch-acrylate-pullulan semi-interpenetrating network polymer (st-AA-PULL) was prepared by a novel two-step aqueous solution microwave method.The environmental factors,efficacy and kinetic models of the cationic dye methylene blue (MB) in aqueous solution were studied.The results showed that the initial concentration of different dyes,pH environment and salt concentration had some influence on the adsorption efficiency of MB,but the product materials still showed a wide range of environmental adaptability.Within MB initial concentration of 0~200 mg/L,the product MB adsorption rate was up to 90%,the concentration of 200 mg/L adsorption capacity was 181 mg/g,the adsorption rate was 91.2%.The product has excellent acid and alkali resistance,and the adsorption capacity of nearly 160 mg/g was still maintained at pH 2.0,and the adsorption rate was 90.9%.Compared to the acidic environment,the alkaline environment was more conducive to the adsorption of cationic dyes by the product.The salt concentration of 0.02~0.10 mol/L,with the increase of the concentration,the adsorption efficiency decreased slowly with the increase of the concentration,but it still had a good salt tolerance.The adsorption rate at a high salt concentration of 0.10 mol/L only decreased by 6.7%.The amount was 152 mg/g.The process of adsorption of MB by st-AA-PULL accorded with the pseudo-second-order kinetics model,and was mainly based on the chemical adsorption process.The isothermal adsorption model was in accordance with the Freundlich model,and the adsorption process was multi-layer adsorption.