Enhanced catalytic reduction/degradation of organic pollutants and antimicrobial activity with metallic nanoparticles immobilized on copolymer modified with NaY zeolite films

Toxic organic pollutants are the major cause of water pollution. Thus, finding a reliable technology for the removal of such pollutants is one of the global priorities for the protection of the natural environment and human health. The MNP's with low-cost and high catalytic efficiency loaded on self-assembled polymeric membranes are promising approach to treat waste water because of their outstanding properties. In this work, novel polystyrene-b-polyisoprene-b-polystyrene block copolymer (BP) virgin and modified composites with NaY zeolite (BP-NaY) were successfully prepared via a simple solution casting method for immobilization of the metal nanoparticles (MNPs). Both the films were impregnated with zero-valent Cu, Ag and CuAg nanoparticles (NPs). The synthesized catalysts were analyzed through FESEM, EDS, FTIR and XRD. The impregnated metal ions on BP or BP-NaY nanocomposites thin films were converted to their corresponding zero-valent metal NPs by using NaBH₄ as a reductant and were evaluated for their catalytic activity in the reduction of various organic pollutants including dyes (MO, CR, MB, ARS), nitroarenes (4-NP, 4-NA, 2/3/4-NB) and antibiotic cefixime. Based on pseudo-first-order kinetics, the rate constant value “k_app” was highest for CuAg@BP-NaY catalyst against all pollutants i.e. 14.7 × 10⁻¹, 40.6 × 10⁻¹, 17.5 × 10⁻¹, 11.6 × 10⁻¹, 12.7 × 10⁻¹, 6.4 × 10⁻¹, 13.2 × 10⁻¹ min⁻¹ for 4-NP, 4-NA, MO, ARS, MB, CR and cefixime respectively. The effect of various parameters on pollutants removal and concurrent degradation of dyes and nitroarenes were also investigated. Catalyst proved to be stable as a slight reduction in the catalyst activity was observed during recyclability. Moreover, the CuAg@BP-NaY showed 19- and 22-mm zone of inhibition against Escheria coli and Staphylococcus aureus respectively. Thus, this study highlighted the catalytic potential of the prepared MNPs in water treatment applications.