Study On The Properties And Preparation Of Chitosan Loaded On Bentonite

Chitin and chitosan are renewable and abundant natural macromolecule compounds, which are nontoxic,biocompatible and biodegradarable,and have antiseptic,bactericidal functions.These biopolymer are easily modified and can be used as macromolecular sorbent.Chitosan is a liner polyamine whose amino groups are readily available for chemical reaction and salt formation with acids and is significant for the research of wastewater sorbent based on chitosan its derivatives . It has become a kind of promising natural macromolecule sorbent which has been applied broadly on wastewater treatment. This work is studied the preparation of chitosan-loaded on bentonite resins and their adsorption properties.It is unreported that the sorbent of chitosan loade on bentonite can be used in waste water treatment ,so that it is necessary to have exploring research in this field. In this paper, three parts of work were included:1. A novel sorbent material based on chitosan loaded on bentonite (shortening: Bent-CTS) was synthesized. The appearance and structure of Bent-CTS were characterized by SEM and IR. IR spectra show that the adsorption of bentonite for chitosan attributes to obvious chemical process. SEM indicates chitosan is loaded on bentonite equably. The special surface area of Bent-CTS is 15.2m~2.g~-1. The experimental data for adsorption reveal Bent-CTS has the best adsorption capacity for Ni~2+,Pb~2+ at pH6.5, pH6.0 and the saturation capacities are 1.87, 1.99 mmol.g~-1 respectively. At the same time, the equilibrium isotherms for adsorption are well correlated to the Langmuir equation and the Freundlich equation; the saturation capacity of Bent-CTS has also no obvious change after regeneration times, so that Bent-CTS is hopeful in waste water treatment.2. The adsorption of sorbrnt adding porogenic agents in the course of sythesis and the effect of the adsorption on zeta potential have been studied. The results of experiments showed that the optimun conditions of adsorption by sorbent were: ethanol in sorbent was 10% and has good sorption properties to Cr~6+,the saturation capacity for Cr~6+ of sorbent has also greater than that of Bent-CTS and uptakes reached 214mg/g, and the adsorption capacities reduced with the rising of the temperature and salinity. With the concentration of metals increasing, the value of zeta potential of sorbent decrease.3. Chitosan reacts with vanillin aldehyde by Schiffs base reaction in water, a polymer product V-B-CTS can be prepared. The molecular structure is as deemed base on the analysis result by infrared spectrum. The results of experiments showed that the modified sorbent has higher adsorption capacities and enhancing the resistance of sorbent against acid than unmodified one and has good kinetic properties-uneasily running off and being regenerated easily.