Mint Extract‐Mediated Synthesis of Silver Nanoparticles Embedded in Microcrystalline Cellulose for Catalytic Decolorization of Cationic and Anionic Dyes

ABSTRACT The elimination of toxic synthetic dyes from wastewater remains challenging due to their remarkable stability and resistance to conventional treatment methods. Catalytic decolorization using sodium borohydride NaBH 4 has emerged as a fast and efficient strategy for transforming these persistent dyes into less harmful products, yet the development of green and sustainable catalysts with high activity, long‐term stability, and broad applicability toward diverse dye pollutants remains a critical priority. This study reports the use of biogenically synthesized silver nanoparticles anchored on microcrystalline cellulose, via a mint extract‐mediated route, as an efficient catalyst for the decolorization of cationic and anionic dyes. Characterization by XRD, FTIR, XPS, UV–vis DRS, SEM–EDS, and TGA confirmed successful nanoparticle formation, well‐distributed morphology, and enhanced thermal stability of the composite compared to pristine MCC, with uniformly dispersed AgNPs of 5–10 nm anchored on the MCC surface. The catalytic performance of MCC@AgNPs was evaluated for the reduction of methylene blue (MB), methyl orange (MO), and allura red (AR), in the presence of sodium borohydride. Kinetic studies revealed the highest apparent rate constant for MB (Kapp = 0.0107 s − 1 ), achieving 98.77% removal in 330 s, followed by MO ( K app = 0.00819 s − 1 , 95.51% removal in 390 s) and AR ( K app = 0.0066 s − 1 , 94.40% removal in 480 s). The catalyst exhibited excellent recyclability, retaining over 90% efficiency for MB degradation after six consecutive cycles, demonstrating its potential as a cost‐effective, and sustainable material for broad‐spectrum dye remediation.