Utilization of agricultural waste: mango peels and pineapple crown leaves as precursors for nanomaterial production for arsenate remediation.

The improper management of agricultural waste can produce particulate matter and greenhouse gases. This study explores a green synthesis approach in which mango peel extract rich in polyphenols is used to produce green nano zero-valent iron (G-NZVI). Furthermore, supporting G-NZVI with nanocellulose isolated from pineapple crown leaves (NCC) enhances the stability and dispersion of NZVI. X-ray diffractometry, zeta potential measurements, scanning electron microscopy with energy-dispersive X-ray spectroscopy, transmission electron microscopy, specific surface area analysis, and X-ray absorption near-edge spectroscopy were used to characterize the properties of the G-NZVI/NCC composites. The adsorption isotherm of arsenate (As) on G-NZVI/NCC demonstrated a maximum adsorption capacity of 5.488 mg·g, which was higher than that of G-NZVI alone. The isotherm model indicated monolayer As adsorption on the homogeneous G-NZVI/NCC surface without lateral interactions between adsorbed molecules. The results revealed that low pH conditions, a high dosage of G-NZVI/NCC, and a low initial concentration of As increased the removal efficiency. The iron oxide layer of G-NZVI/NCC forms a strong surface complex, facilitating the formation of an inner sphere with As across a normal pH range and providing a cost-effective and eco-friendly solution for arsenic-contaminated water.