Preparation And Characterisation Of Bentonite Compound Chitosan And Its Adsorption Behaviour Of Organic Dyes

A bentonite composite absorbent was prepared by in-situ intercalation polymerization of chitosan directly intercalating into modified-bentonit, taking the Ca-bentonite from Linan as raw material, get the sodium modification and acidified bentonite. investigated its best preparation condition by the determination of interlayer spacing and loading amount of chitosan. The structure and composite mechanism of obtained composite adsorbent was studied by using small angle X-ray diffraction(XRD), scanning electronic microscopy(SEM), infrared spectroscopy (FIRT). Carboxymethyl chitosan(CMC) was prepared for improving the water solubility of chitosan.The adsorption performance of all obtained composite adsorbent and modified bentonite to basic fuchsin and indigo was studied, compared their adsorption capacity, and fitted the experimental date which had highest adsorption capacity by utilizing typical adsorption isotherm models.The results showed that the optimal condition for prepared Nabent-CTS was that chitosan concentration at 20g/L,4h stirring time and 45℃; the Hbent-CTS was 20g/L,2h and 65℃.Na-bentonite compound chitosan, chitosan had been inserted into the sodium bentonite's layer successfully by electrostatic attraction. As for HBent-CTS, the disorder state between interlayers was changed by enhanced van der waals force. Carboxymethyl chitosan had been successfully prepared, and the experimental results revealed that its water solubility was improved, but the adsorption capacity of bentonite compound Carboxymethyl chitosan was not increased significantly, Carboxymethyl chitosan had not been inserted into the modified bentonite's layer, just adhered to the surface of bentonite. Compared the adsorption capacity of both obtained adsorbent showed that the NaBent-CTS and HBent-CTS were best. Fitting the experimental data of NaBent-CTS and HBent-CTS by utilizing typical adsorption isotherm models, show Langmuir's adsorption process well relevance to the Freundlich, and the adsorption mechanism of basic fuchsin and indigo were hydrogen bonding, electrostatic force and physical adsorption.