Photocatalytic and Antibacterial NiO/MgO Nanocomposites for Efficient Dyes Removal From Industrial Wastewater

Abstract

The presence of non-biodegradable industrial waste, particularly dyes, has led to pollution of aquatic ecosystems. Consequently, it is crucial to devise effective strategies to remove industrial contaminants. This study focused on creating nanomaterials for wastewater treatment. NiO/MgO nanocomposites (NCs) were produced via chemical precipitation and subsequently characterized. X-ray diffraction (XRD) verified the crystalline nature of NiO/MgO with a face-centered cubic (FCC) structure, which promoted strong interfacial interactions. Scanning electron microscopy (SEM) showed that the NiO/MgO NCs agglomerated into spherical and irregular shapes, whereas transmission electron microscopy (TEM) confirmed a size range of 65–100 nm. UV–vis spectroscopy indicated absorption in the UV–vis spectrum, suggesting its photocatalytic potential. The photocatalytic performance of the NiO/MgO NCs was assessed for organic dyes such as methylene blue (MB), Congo red (CR), and methyl orange (MO) under UV–vis light, demonstrating notable efficiency at higher dye concentrations. The highest degradation efficiency was recorded for CR (∼77% at 100 ppm over 60 min), followed by MO (∼71.6%) and MB (∼70%). The enhanced photocatalytic activity was linked to the nanostructured morphology, effective charge separation, and decreased electron-hole recombination. NiO/MgO NCs also showed strong antibacterial properties against both gram-positive and gram-negative bacterial strains. Antimicrobial mechanisms include the production of reactive oxygen species (ROS), disruption of membranes, and interactions with metal ions, which demonstrate the multi-functionality of NiO/MgO NCs as efficient wastewater treatment agents. © 2025 Wiley-VCH GmbH.