Recent advances in zinc oxide nanoparticles for dye removal: Challenges and future directions – A review

The removal of hazardous dye molecules from industrial wastewater remains a significant environmental challenge, driving the search for cost-effective and efficient treatment methods. Though many techniques for removing dye from aqueous solutions have been developed and used with varying degrees of success, adsorption has gained recognition due to its simplicity, low cost, and high efficiency. Zinc oxide nanoparticles (ZnO NPs) have recently emerged as promising adsorbents owing to their high surface area, controllable surface properties, and strong dye–adsorbent interactions. This review presents a comprehensive analysis of recent advancements in the application of ZnO NPs for dye adsorption, critically evaluating their performance and addressing the challenges associated with their use. Particular emphasis is placed on the underlying adsorption mechanisms and the role of ZnO NPs in enhancing wastewater treatment efficacy. By identifying existing knowledge gaps and proposing targeted research directions, this review provides critical insights to guide the development of more effective ZnO NP-based adsorption systems in real-world wastewater treatment applications.