Green Fabrication of NiO–SnO2 Nanocomposites Using Grape Extract and Their Application in Cadmium Removal from Water

In this work, an environmentally benign approach was developed for the preparation of NiO–SnO 2 nanocomposites employing grape extract as a natural reducing and stabilizing medium. The bio-assisted synthesis route eliminates the need for hazardous chemicals and promotes sustainable material production. The obtained nanocomposites were comprehensively characterized using X-ray diffraction (XRD) to determine crystalline phases, field-emission scanning electron microscopy (FESEM) to investigate surface morphology, dynamic light scattering (DLS) for particle size distribution, and Brunauer–Emmett–Teller (BET) analysis to evaluate specific surface area and porosity. The adsorption capability of the synthesized material was examined for the removal of Cd 2+ ions from aqueous solutions at room temperature. Experimental findings demonstrated that the grape-extract-derived nanocomposite exhibited superior adsorption efficiency compared to conventionally prepared counterparts. Furthermore, adsorption kinetics and thermodynamic parameters were evaluated to gain deeper insight into the interaction mechanism between cadmium ions and the nanocomposite surface. The results confirm the potential of this green-synthesized NiO–SnO 2 system as an effective and sustainable adsorbent for heavy metal remediation in water treatment applications.