Developing a cost-effective and eco-friendly adsorbent/photocatalyst using biomass and urban waste for crystal violet removal and antimicrobial applications

Recycling and efficient management of urban solid waste, including medical X-ray sheets (MXS) and food waste, pose a significant challenge for conserving environmental and water resources. Exploiting waste materials, this study developed a cost-effective, eco-friendly, and efficient adsorbent/photocatalyst to eliminate crystal violet (CV) dye and deliver CV-free water. To design the adsorbent/photocatalyst, silver nanoparticles (AgNPs) sourced from medical X-ray sheets (MXS) were amalgamated with carbon derived from potato peels (PPC) to create a mesoporous AgNPs@PPC nanocomposite. The study systematically investigated the impact of pH, time, adsorbent/photocatalyst amount, temperature, and initial CV concentration. The findings show that the AgNPs@PPC successfully removes over 98% of CV dye at pH 7 within 30 min under UV irradiation. The interaction mechanism between AgNPs@PPC and CV dye was elucidated through kinetic, isotherm, zeta potential, scavenger test, and density functional theory (DFT) analyses. The AgNPs@PPC shows remarkable efficiency even after five cycles to reduce overall wastewater remediation expenses. The AgNPs@PPC nanocomposite showed satisfactory antibacterial performance against B. subtilis, E. coli, P. vulgaris, and V. parahaemolyticus. The findings revealed that the AgNPs@PPC nanocomposite is an effective adsorbent/photocatalyst for CV removal, offering several key features: (i) recycling biomass and urban waste to protect environment; (ii) utilizing cost-effective and eco-friendly materials; (iii) achieving high efficiency in CV removal under neutral pH conditions; (iv) minimizing waste volume through multiple reuse cycles; (v) the porous nature of AgNPs@PPC enhances CV diffusion, thereby increasing removal efficiency; and (vi) demonstrating good antibacterial activity. To our knowledge, no existing reports have utilized mesoporous MXS-derived AgNPs combined with potato peel-derived carbon for CV dye removal via adsorption and photocatalytic degradation methods and for antibacterial application. This underscores the innovative potential of these materials in wastewater dye removal.