Abstract

Alizarin dye, a persistent and hazardous contaminant in aquatic environments, presents a pressingenvironmental concern. In the quest for efficient removal methods, adsorption has emerged as a versatile andsustainable approach. This study focuses on the development and application of Zinc Oxide/Nickel Oxide (ZnO/NiO) nano-composites as adsorbents for alizarin dye removal. These semiconducting metal oxide nanocompositesexhibit synergistic properties, offering enhanced adsorption capabilities. Key parameters affectingalizarin removal, such as contact time, adsorbent dosage, pH, and temperature, were systematically investigated. Notably, the ZnO/NiO nano-composite demonstrated superior performance, with a maximum alizarin removalpercentage of 76.9 % at pH 6. The adsorption process followed a monolayer pattern, as suggested by theLangmuir model. The pseudo-second-order kinetics model provided a good fit to the experimental data. Thermodynamic analysis indicated that the process is endothermic and thermodynamically favorable. Thesefindings underscore the potential of ZnO/NiO nano-composites as effective and sustainable adsorbents for alizarindye removal, with promising applications in wastewater treatment and environmental remediation.