Design and fabrication of nanocomposite adsorbents for dairy industry wastewater treatment

The dairy industry produces a significant volume of effluents that contain various pollutants, which causes environmental issues. In this study, the fabrication and performance of nanocomposite adsorbents incorporating activated carbon (AC), calcium alginate (CA), and nanosilica, as a simple, cost-effective, and eco-friendly approach to treat dairy wastewater, aiming to enhance food processing sustainability by reducing water consumption, minimizing wastewater, and supporting the Water-Food-Environment Nexus. The nanoparticles were synthesized using sand extraction in an environmentally friendly approach with a size of 30–45 nm. Several techniques such as X-ray fluorescence (XRF), X-ray diffraction (XRD), ultraviolet–visible spectroscopy (UV–VIS), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) were used to characterize the materials. Furthermore, the nanocomposite adsorbent performance and efficiency in removing chemical oxygen demand (COD) were assessed through batch experiments. The nanocomposite adsorbents’ optimal conditions were investigated through batch experiments, achieving a 99.7% COD removal in dairy wastewater treatment. The best results were obtained with a 4-h contact time, pH of 2, and nanosilica dosage of 10%, demonstrating the adsorbent’s high efficiency in organic pollutant removal. However, the adsorption isotherm, kinetic, and thermodynamic studies were carried out and the best-fitted models of isotherm, and kinetic models were Langmuir, and pseudo-second-order reaction, respectively. The thermodynamic reaction of this study is related to being endothermic.