NiO as a promising photocatalyst for wastewater purification: A review

¹ Department of Chemistry, Research & Incubation Centre, Rayat Bahra University Chandigarh-Ropar NH 205, Greater Mohali, Punjab, 140103, India
² Facultad de Ingeniería, Arquitectura y Diseño, Universidad San Sebastian, Bellavista 7, Santiago. Chile
³ Department of Refrigeration and air Conditioning Techniques, College of Technical Engineering, the Islamic University, Najaf, Iraq

^* Corresponding author: bhattumonika@gmail.com

Abstract

Water scarcity and contamination represent critical challenges in the twenty-first century, with only a fraction of the Earth’s water being suitable for human use. Various pollutants, including heavy metals, dyes, and pharmaceuticals, compromise water quality, leading to serious environmental and health issues. Traditional wastewater treatment methods often fall short in effectively removing these contaminants. Photocatalysis has emerged as a promising solution, particularly with the use of nickel oxide (NiO) as a photocatalyst. This review explores the fundamentals of photocatalysis, the unique properties of NiO, and its applications in wastewater treatment. NiO is a great option for degrading the organic contaminants because it has a suitable band gap for light absorption and effective charge carrier separation. The synergistic effects of NiO composites with other semiconductors, such as TiO₂ and ZnO, further enhance photocatalytic efficiency. Recent advancements in NiO photocatalysis indicate its potential for large-scale applications, addressing the urgent need for sustainable water purification technologies.