Preparation And Adsorption Of Montmorillonite/Amphoteic Starchcomposites

Applied starch(St),methacryloyloxyethyltrimethylammonium chloride(DMC),acrylic acid(AA)and montmorillonite(MMT)as the raw materials,MMT/St-g-P(DMC-AA)composites were prepared by aqueous solution polymerization.The adsorption properties of the composites to MB,MO,chromium(VI)and lead(II)were studied.The effects of adsorption time,initial pH values of the adsorbates,adsorbent dosage and initial adsorbates concentration on the adsorption capacity were investigated.The adsorption kinetics,adsorption thermodynamics and adsorption isotherm model were studied.The adsorption mechanism was also preliminary explored.The conclusions were as follows:(1)The prepared composites have a good adsorption capacity of MB and MO,and the adsorption capacity were 196.013mg/g ? 142.293mg/g,respectively.With the increasing the temperature and pH values,adsorption capacity of MB increased,but that of MO decreased.With the increasing the initial concentrations of MB and MO,adsorption capacity increased.With the increasing of monomer ratio of AA and DMC,adsorption capacity of MB increased,but that of MO decreased.The adsorption kinetic data of MB and MO by composite were fitted to the Lagergren pseudo second order rate equation and Freundlich adsorption isotherm model.The adsorption mechanism of ionic dyes by composite included electrostatic force,hydrogen bond,van der Waals force,hydrophobicity and ion exchange.The main control step of the adsorption rate was liquid film diffusion.(2)The prepared composites have a good adsorption capacity of lead(II)and chromium(VI),and the adsorption capacity were 146.425 mg/g and 34.673 mg/g,respectively.With the increasing the adsorption time,the adsorption capacity of lead(II)and chromium(VI)increased,and reached saturate at last.With the increasing the initial concentrations of lead(II)and chromium(VI),adsorption capacity increased.With the increasing of monomer ratio of AA and DMC,adsorption capacity of lead(II)and chromium(VI)decreased.The adsorption kinetic data of lead(II)and chromium(VI)by composite were fitted to the Lagergren pseudo second order rate equation and Freundlich adsorption isotherm model.