FEASIBILITY STUDY ON PREPARATION OF RICE STRAW NONWOVEN COATED WITH CHITOSAN FOR REACTIVE DYE ADSORPTION

Rice straw is the most abundant agricultural waste material in Thailand. Therefore, this research was interested in utilizing rice straw and adding value by preparing a reactive dye bioadsorbant. The aims of this research were to prepare rice straw nonwovens by the wet-laid process, study chitosan-coated nonwovens by the dip coating method, and evaluate the reactive dye adsorption capacity of the coated nonwovens. The ratio of weight per unit area of the prepared nonwovens was controlled. The nonwovens were dipped in chitosan solutions (0.5, 1, and 1.5 wt% of chitosan) to prepare chitosan coated nonwovens. Reactive dye adsorption capacity, chemical structure, morphology, and physical properties of the nonwovens were investigated. It was found that rice straw nonwoven coated with chitosan increased in thickness, hardness, and water resistance properties with increasing chitosan concentration. Chitosan-coated nonwoven, at 15% chitosan concentration and a contact time of 72 hours, was able to adsorb 38.40% of the reactive azo dye, C.I. Reactive Blue 194 (50 mg/L). The dye absorbency of the chitosan-coated nonwovens increased with the increase in the chitosan-coated concentration and the contact time. In addition, the chitosan-coated nonwovens could remain on rice straw cellulose nonwoven surfaces under reactive dye immersion for at least 72 hours without change. The results indicated that rice straw nonwovens coated with chitosan by the dip coating method had reactive dye adsorption abilities.