Journal of Materials Science, Vol.53, No.3, 2277-2289, 2018
Preparation of green chelating fibers and adsorption properties for Cd(II) in aqueous solution
Chitosan chains (CTS) were grafted onto polyvinyl alcohol fibers (PVAf) with the aid of coupling agent gamma-glycidoxypropyltrimethoxysilane, producing grafted fibers PVAf-g-CTS. Then, chloroacetic acid (CA) was used to react with the chitosan chains on the PVAf-g-CTS surface via nucleophilic substitution reaction to produce fibrous PVAf-g-CACTS with multiple adsorption sites. The products were characterized by using FTIR, SEM, XRD and XPS, revealing that the reaction followed the S (N) 2 mechanism. Optimum parameters, including a reaction temperature of 50 A degrees C and a mass ratio of PVAf-g-CTS to CA of 1:0.12, were determined for the reaction. Adsorption experiments confirmed that PVAf-g-CACTS showed greater adsorption characteristics for Cd(II) in aqueous solutions compared with PVAf-g-CTS and PVAf. In particular, the rate of Cd(II) uptake by using PVAf-g-CACTS was higher, and the equilibrium was reached within 80 min. When pH was 7, the saturated adsorption capacity reached 47.65 mg g(-1). The adsorption kinetics conformed to the pseudo-second-order model, and the adsorption process was in accordance with the Langmuir and Temkin isotherm model. Adsorption-desorption cycle experiments showed that PVAf-g-CACTS had good performance of reuse, and the adsorption mechanism was analyzed further by using XPS.