Green synthesis of ZnO nanoparticles using semi- conductor biosolid for ammonium removal from synthetic municipal wastewater

The rapid rise in urbanization and industrial activity has intensified municipal wastewater generation, posing environmental and public health risks. Ammonium nitrogen (NH₄⁺–N) is a key pollutant due to its toxicity and role in eutrophication. Conventional removal methods are often costly and energy-intensive, prompting the need for sustainable alternatives. This study introduces a green synthesis of zinc oxide nanoparticles (ZnO NPs) using sugarcane bagasse (SCB)-based biosolid derived from electronic sludge, serving as both reducing agent and support matrix. The resulting ZnO NPs–SCB were characterized via UV–Vis spectrophotometry, FTIR, and FESEM, confirming key functional groups, semi-spherical morphology, and a quantum confinement absorption peak at 377 nm. A central composite design under response surface methodology (RSM) optimized ammonium removal conditions, achieving 43.72% efficiency. While moderate, this performance highlights the potential of biosolid-derived ZnO NPs for nutrient removal. The study presents a novel integration of waste valorization and green nanotechnology, offering a scalable, low-cost option for decentralized wastewater treatment. Although advanced characterizations such as XRD, BET, and zeta potential were beyond this study’s scope, their future inclusion is encouraged. Overall, this work underscores the potential of biosolid-based nanomaterials in eco-efficient wastewater treatment, offering a low-cost, scalable pathway aligned with circular economy and resource recovery principles.