Abstract:

Polythioether type cotton cellulose(PTCC), a functional material, was synthesized by the etherification of cotton cellulose and chloromethylthiirane in an alkaline medium. The effect of pH on adsorption capacity of PTCC for cationic dyes was investigated. The adsorption kinetics and thermodynamics of cationic dyes on PTCC were studied. The experimental results show that neutral condition favored the adsorption. At 298 K, pH=7.0, the adsorption approached to equilibrium in 2 h, the saturated adsorption capacities of PTCC for basic Blue B, basic Blue R and night blue were 726, 652 and 320 mg/g, respectively. The adsorption of cationic dyes on PTCC followed the secondorder kinetic model, the adsorption rate constant k2 increased with the decrease of temperature, indicating that low temperature favors the adsorption. The negative values of ΔG, ΔH and ΔS suggest that the adsorptions are spontaneous and exothermic processes, which were achieved mainly by Vander Waals force. The adsorption isotherms fit well with the Langmuir equation, which can be explained as a monolayer adsorption.

Key words: polythioether type cotton cellulose, cationic dyes, adsorption, thermodynamics, kinetics