Kinetic studies on Cr(III)-binding behavior of collagen fiber functionalized by amino- and carboxyl-terminated hyperbranched polyamide

Abstract

Two kinds of insoluble collagen fiber (CF) were prepared by grafting amino- and carboxyl-terminated hyperbranched polyamide into collagen fiber using the cross-linking and terminal groups modification methods: (1) grafting amino terminated hyperbranched polyamide to CF by glutaraldehyde, and (2) condensation of the resulting carboxyl with glyoxylic acid. Their structures were characterized by FT-IR, SEM-EDX, ion distribution, and XRD. Because of the condensation of glyoxylic acid, the adsorption peaks of carboxyl groups occurred at 1,740 cm−1 in the FTIR spectra. The adsorption capabilities of the products for Cr(III) were studied by batch experiments. The pseudo-first-order, pseudo-second-order, and intra-particle diffusion model equations were used for the kinetic studies. The results showed that the products exhibited better adsorption capabilities for Cr(III). The adsorption capability of carboxyl-terminated product was higher than that of amino-terminated one and this is attributed to the carboxylic functional groups in the carboxyl-terminated product, which are responsible for their cationic ion exchange phenomenon. It was also observed that kinetic data correspond very well to the pseudo-second-order equation.