Preparation of amine-functionalized cellulose–silica composite for the removal of benzoic acid and triclosan from water

In this study, an amine-functionalized cellulose–mesoporous silica composite (Cell-Sil-NH2) was constructed for the adsorption of benzoic acid and triclosan from water. First, cellulose was extracted from sugarcane bagasse via acid (0.5% HCl) and alkaline (0.5% NaOH) hydrolysis, followed by bleaching with sodium chlorate and hydrogen peroxide to remove pectic compounds. A mesoporous silica layer was then coated onto the cellulose via a sol–gel method using tetramethyl orthosilicate, and the composite was functionalized with (3-aminopropyl)trimethoxysilane to introduce amine groups. The resulting Cell-Sil-NH2 was characterized using FTIR, SEM, XRD, BET surface area analysis, BJH pore size distribution, and TGA. The effects of initial pollutant concentration, adsorbent dosage, contact time, and pH were evaluated and the optimum conditions were determined. Benzoic acid and triclosan were found to have adsorption capacities of 471.34 mg g−1 and 489.75 mg g−1, respectively. Adsorption of BA and TC onto Cell-Sil-NH2 followed the Langmuir model and pseudo-second-order kinetics, according to isotherm and kinetic studies, indicating monolayer adsorption controlled by surface interactions. Regeneration studies revealed that Cell-Sil-NH2 could be effectively reused for up to 50 cycles.