Modification Of Natural Macromolecule Materials And Study On Their Absorption Of Dyes

Some natural macromolecular materials such as chitosan,β-cyclodextrin and guar gum were modified in this research. The effect of absorption capacity of derivatives by changing the environmental condition was studied, which could provide a useful guide for the treatment of printing and dyeing wastewater.Theβ-cyclodextrin microsphere was prepared firstly, and then the chitosan was bonded on it to form a new derivative. XRD, FTIR, SEM and surface area determinator were used to characterize the structure and micro-morphology of derivatives and stuff. Raw materials were compared with derivative in absorbing methyl orange through changing stirring time, temperature and pH value. It was proved that the absorption capacity of chitosan bondedβ-cyclodextrin microsphere was better than that of chitosan and P-cyclodextrin microsphere. In addition, the absorption capacity of derivative was increased with temperature and pH value, the maxium absorption capacity was 20 mg·g-1. The process of absorption was fitted with Freundlich absorption model well. Moreover, the absorption action was an unspontaneously endothermic process. Then the guar gum was bonded toβ-cyclodextrin microsphere, a series of derivatives were synthesized. The structure of stuff and polymer were characterized by XRD and FTIR. The content ofβ-cyclodextrin within derivatives was determined using phenolphthalein spectrophotometry. By changing experimental conditions and types of absorbents, the absorption capacity of derivatives was studied. It was proved that the derivative which was prepared in 2 hours, when stuff mass ratio of chloro-hydroxypropyl guar gum,β-cyclodextrin microsphere and sodium carbonate was 0.6:0.8:1.0, the best result among the series of derivatives was 24mg-g"1. At last, the cationic etherification agent was grafted to the guar gum bonded P-cyclodextrin microsphere, in order to enhance the absorption towards acid red GR. The absorption capacity towards acid red GR was studied. It was proved that under the condition of pH value at 7.5, stirring time at 50 min, Zeta potential value at-5.53mv,50 mg-g"1 acid red GR was absorbed in room temperature.Moreover the organic-inorganic hydrogels were prepared using in-situ radical polymerization of acrylamide monomers in the suspension of nano-laponite clay and nano-montmorillonite respectively. The added amount of inorganic materials and monomer, the temperature concentration, and the value of pH were changed, the absorption capacity of hydrogels towards basic fuchsin was studied. It was proved that the absorption capacity was increased slowly with the increase of the added amount of inorganic materials. When the weight of acrylamide monomers was increased in laponite clay complex hydrogel, their absorption capacity was increased obviously from 4.62 mg-g-1 to 24.45 mg-g-1. Under the same experimental conditions, the absorption capacity of montmorillonite complex hydrogel was decreased obviously; but for the two complex hydrogels, when the pH value and temperature of dye solution were increased, the absorption of laponite clay complex hydrogel increased by 11.10 mg-g-1 and 1.84 mg-g-1 respectively. On the contrary, there was no much change in the absorption of montmorillonite complex hydrogel.