Facile and sustainable modification for improving the adsorption ability of sugarcane bagasse towards cationic organic pollutants

Using low-cost agro-industrial wastes and by-products derived from lignocellulosic biomass for adsorption is considered to be an affordable and sustainable way to tackle the burning issue of cationic pollution in the water bodies, while its relatively low adsorption capability limits its large-scale application. In this study, a green, rapid, simple, and cheap method was developed by using ozone to improve the adsorption abilities of sugarcane bagasse (SB). The relationship between the chemical compositions and functional groups of SB after ozone modification and its adsorption abilities was studied. Results showed that ozone modification under very low ozone consumption (~ 1.5 wt%) could efficiently increase the pore volume, surface area, and carboxyl groups, change the chemical compositions of SB, and does not significantly change its morphology, thereby ensuring the good adsorption performance of SB and easy recycling from the water bodies. The maximum adsorption rate and equilibrium adsorption capacity of SB for positively charged methylene blue (MB) were increased about 33.3% and 11.3% than the original SB (MB concentration = 100 mg/L, SB concentration = 5 g/L, initial solution pH = 6, temperature = 30 °C). Besides, ozone-modified SB maintained its high adsorption capability even at a high NaCl concentration of 0.6 M and high pH of 9. For cationic polymer with high charge densities, the adsorption capacity of milled SB increased about 125.4%. Graphical Abstract