Valorization of agro-industrial wastes of sugarcane bagasse and rice husk for biosorption of Yellow Tartrazine dye.

The use of agro-industrial wastes as biosorbents is a promising alternative for sustainable, economical and effective adsorption. However, few studies evaluate the use of Brazilian agro-industrial waste as biosorbents without physicochemical pre-treatment. This study explored the potential of sugarcane bagasse (SCB) and rice husk waste (RHW) as low-cost biosorbents for yellow tartrazine dye removal. Characterization of the materials were carried out using ATR-FTIR, SEM, pHPZC and lignocellulosic composition. Cellulose and hemicellulose were the major constituents of both materials. By the Box-Behnken experimental design, the response surfaces indicated maximum removal of 60.1% for SCB and 83.1% for RHW. While the qmax of SCB and RHW for tartrazine were relatively low at 2.45 ± 0.03 mg g-1 and 3.55 ± 0.02 mg g-1, respectively, the potential for achieving higher dye removals by increasing the adsorbent dosage in large-scale applications warrants further investigation. For both biosorbents, the pseudo-second-order kinetic model and Brouers-Sotolongo isotherm provided the best fit for the data, and the adsorption processes were spontaneous and exothermic. In conclusion, SCB and RHW demonstrated high tartrazine removal, promoting sustainable agro-industrial waste management.