Chemical modification of sugarcane bagasse with chitosan for the removal of phosphates in aqueous solution

Sugarcane bagasse is the major solid waste product of the sugarcane industry. As a plant-derived biomass, it is an attractive environmentally friendly alternative to petroleum-based materials. Being a non-food agriculture product, its use as a raw material is more widely accepted. Sugarcane bagasse is comprised mainly of cellulose, hemicellulose and lignin. The aim of this study was to develop a low-cost anion exchange adsorbent from sugarcane bagasse for the removal of phosphates in aqueous solution. The adsorbent was developed by crosslinking chitosan with cellulose that was extracted from sugarcane bagasse. To obtain cellulose for covalent linkage with chitosan, the bagasse was pretreated with dilute sodium hydroxide and sulphuric acid solutions followed by bleaching with hydrogen peroxide. After this process, the material was modified using chitosan functionalized with epichlorohydrin to obtain the modified bagasse (SCB-CS). SCB-CS was characterized using Fourier transform infrared spectroscopy (FTIR) analysis that indicated the successful reduction in the content of lignin and hemicellulose. The grafting of chitosan derivatives within the matrix of cellulose was confirmed by intense peaks at 1651 cm−1 and 1589 cm−1 observed on the modified SCB-CS. SCB-CS was evaluated for its ability to remove phosphates from synthetic waste water and 61.51% removal and an adsorption capacity of 52.33 mg/g, where the initial concentration was 28.36 mg/L at an adsorbent dosage of 0.1 g was achieved.