We report a green route to Ag–TiO2 nanocomposites using an Allium tuberosum extract, rich in organosulfur and polyphenolic constituents, as a dual-function biogenic reducer and stabilizer, enabling efficient Ag+→Ag0 conversion and capping of Ag–TiO2 without the use of harsh reagents. The nanocomposites are formulated into chitosan-based inks for direct ink writing (DIW) of porous, mechanically robust, reusable membranes (optimal formulation T@5Ag–5ATE–CS) with a homogeneous Ag dispersion. Multiscale characterization (SEM/TEM, XRD, FTIR, UV–vis DRS, EDS mapping) confirms metallic Ag0 uniformly decorating TiO2 and an extended visible-light response attributable to strong localized surface plasmon resonance. Under near-UV/visible irradiation, the membranes decolorize Remazol Midnight Black RGB dye with pseudo-first-order kinetics, yielding kapp up to 5.99·10–3 min–1 with R2 ≈ 0.99 and outperforming pristine TiO2. Response surface methodology identifies an optimum at pH 5.67, 28.87 mg·L–1 dye, and 0.0257 g catalyst, delivering a predicted 96.41% versus experimental 95.07% removal (validation error 1.39%) with excellent model statistics (R2 ≈ 0.995). The combined effects of Allium-tuberosum-assisted Ag plasmonics, TiO2 photocatalysis, and chitosan-enhanced adsorption underpin the high photocatalytic activity and reusability, highlighting a scalable, eco-friendly pathway to printable photocatalytic/antimicrobial membranes for wastewater treatment.
Huyen et al. (Thu,) studied this question.