Functionalized Agave Bagasse Hydrochar for Reactive Orange 84 Removal: Synthesis, Characterization, and ANN–GA Optimization

Functionalized carbon-based materials have recently attracted attention for the efficient removal of complex pollutants, including dyes. In this study, agave bagasse, an abundant by-product of the Mexican tequila industry, was used as biomass to produce H2SO4-modified hydrochar (HC) for the removal of Reactive Orange 84 (RO84). FTIR-ATR analysis revealed characteristic signals of –SO3H groups in the functionalized HC. BET characterization showed a broad range of surface areas and pore volumes, with pore radio indicating nano-, micro-, and mesoporous structures, depending on the acid concentration used during synthesis. TGA and XRD analyses indicated that higher acid concentration promoted the depolymerization of biomass components. Adsorption assays demonstrated that increasing H2SO4 concentrations enhanced dye removal. Post-adsorption FTIR-ATR analysis revealed signal shifts consistent with interactions between sulfonated groups and dye RO84. Statistical and mathematical analyses showed that optimal results were achieved by combining high acid concentrations during HC synthesis with high HC dosages during adsorption.