Eco-Friendly Carboxymethyl Cellulose-Functionalized Binary (ZnS, In ₂ S ₃ ) and Ternary (Zn–In–S) Quantum Dot Nanophotocatalysts for the Advanced Photodegradation of Organic Dye Pollutants in Water

High Resolution Image Download MS PowerPoint Slide Rapid urbanization and industrialization have led to severe water contamination, particularly from irresponsible discharges or accidental spills of synthetic dyes. Environmental nanotechnology, specifically semiconductor quantum dots (QDs), offers disruptive solutions for the photocatalytic degradation of organic pollutants. In this study, binary (ZnS and In 2 S 3 ) and ternary (Zn–In–S) QDs functionalized with carboxymethyl cellulose (CMC) were synthesized via a sustainable, aqueous colloidal route. The CMC biopolymer served as a macromolecular template and stabilizing ligand for the nucleation and controlled growth of the QD. As nanocatalysts, they were evaluated for the photodegradation of methylene blue (MB, cationic) and methyl orange (MO, anionic) model dyes under UV irradiation across various pH conditions (3.0, 5.0, and 7.0). The results confirmed the formation of colloidal nanocrystalline QDs stabilized by CMC, with an average size of approximately 3 nm and optical properties dependent on the core chemical composition. Photocatalytic assays demonstrated removal efficiencies of 30–70%, with optimal degradation at pH 5.0, following the pseudo-second-order model. Hence, these findings demonstrate that CMC-stabilized QDs can provide a sustainable, potentially scalable nanoplatform for advanced oxidative treatment of polluted water.