Synthesis and characterization of cellulose-based adsorbent for removal of anionic and cationic dyes

Synthetic dyes are widely used in textile, paper, plastic, and other industries, which are toxic and harmful to environment and human. Adsorption is an efficient method to control wastewater. Cellulose is an abundant, renewable, and ecofriendly polymer produced by plants and trees. An adsorbent for removal of dyes was successfully prepared by grafting amino-terminated hyperbranched polymer (NH2-HBP) and beta-cyclodextrin (beta-CD) onto cotton fibers in this study. The adsorbent were characterized using Fourier-transform infrared spectroscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy analysis. The influences of adsorption parameters in a batch mode including initial solution pH, contact time, and dye initial concentration were evaluated in the experiments. The experiment results showed that the adsorption equilibrium was reached within 6h for Congo red and within 4h for methylene blue. Both the adsorption isotherms and kinetic studies showed that the behaviors of Congo red and methylene blue removal by the adsorbent based on cotton fibers conformed with Freundlich model and fitted pseudo-second-order model, respectively.