Eggshell waste materials-supported metal oxide nanocomposites for the efficient photocatalytic degradation of organic dyes in water and wastewater: A review

Pollution from dye-containing water and wastewater is increasingly a global concern. Traditional treatment technologies, such as membrane separation, adsorption, and chemical precipitation, have limitations such as incomplete removal, high costs, and a lack of sustainability. Photocatalytic degradation using metal oxide (MO) semiconductors has recently replaced these methods. However, MO's limitations, such as UV radiation's operating range and the electron-hole pair's recombination, have limited their applications. The applications of eggshell waste materials (ESWMs) as a cost-effective, eco-friendly, and sustainable support for MO semiconductor synthesis are gaining popularity, addressing MO limitations and improving photocatalytic performance. This paper discusses the efficient photocatalytic removal of organic dyes from water and wastewater using ESWM-supported MO nanocomposites. Literature surveys and compilations confirmed the exceptional photocatalytic performance of ESWM-supported MO nanocomposites, with an average 92 % organic dye degradation capacity compared to pure MO, highlighting the potential for novel, economical, and environmentally friendly techniques for tackling water pollution problems.