Experimental exploration of QbD employed bio-inspired chitosan/zinc oxide nanocomposites for water remediation

Chitosan (CS), a naturally occurring biopolymer obtained from chitin, has garnered considerable interest in environmental remediation owing to its distinctive attributes. Its inherent biodegradability and exceptional antimicrobial, photocatalysis, and ultraviolet protective characteristics render it a promising polymer for advancing sustainable applications. This study presents the eco-synthesis of Zinc oxide nanoparticles (ZnONPs) from Moringa oleifera (MO) and the development of chitosan-conjugated nanocomposites (MO-CS/ZnONCs) for environmental bioremediation. Box-Behnken design was used to optimize and analyze the formulation conditions. The biosynthesized nanoparticles and nanocomposites were characterized and evaluated for water purification, photocatalytic degradation of Malachite Green (MG) dye, antioxidant, and antibacterial potential. The formation of MO-ZnONPs and MO-CS/ZnONCs was confirmed through a color change, UV-visible spectroscopy, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The nanoparticles and nanocomposites exhibited sizes of 402 nm and 485 nm with PDI values of 0.254 and 0.306, respectively, and zeta potentials of -25 mV and - 12 mV. Both MO-ZnONPs and MO-CS/ZnONCs showed vigorous radical scavenging activity in DPPH and ABTS assays. In photocatalytic degradation studies, MO-CS/ZnONCs demonstrated excellent 99.54 % degradation of MG dye after 40 min of irradiation, significantly outperforming MO-ZnONPs (60 %) and MO extract (47 %). In water treatment studies, MO-CS/ZnONCs reduced total dissolved solids, salinity, and electrical conductivity in groundwater, indicating their potential for environmental remediation. Moreover, the MO-CS/ZnONCs exhibited significant antibacterial activity against selected bacterial pathogens. The results suggest that MO-ZnONPs and MO-CS/ZnONCs hold promising applications in water purification, photocatalysis for dye degradation, and as bioactive agents. These findings provide a sustainable approach to environmental bioremediation, offering practical solutions for water treatment and antimicrobial applications.