A review on recent advances in selective and sensitive detection of heavy toxic metal ions in water using g-C3N4-based heterostructured composites

Abstract

The fabrication of g-C₃N₄ nanosheet-based sensing platforms for the detection or removal of heavy toxic metal ions from wastewater has attracted a great deal of interest due to their unique properties because most of the metal ions are carcinogens and lead to serious health concerns by producing free radicals. Hence, fast and accurate detection of metal ions has become a critical issue. Among various metal ions, As(III), Cd(II), Pb(II), Hg(II), Cr(VI), Cu(II), and Ag(I) are considered to be highly toxic. To detect these toxic metal ions, colorimetric, fluorometric, and electrochemical sensors with interfaces, such as various g-C₃N₄ nanosheet-based composites, have been widely studied as potential adsorbents due to their unique physicochemical properties, such as structural variability, chemical strength, low density, and the possibility of large scale fabrication. This comprehensive review summarizes the recent studies on the selective and sensitive detection of various inorganic contaminants including mainly heavy metal ions by g-C₃N₄ nanosheet-based multi-component composites as nanosensors and also discusses valuable information for applications of these nanosensors in water and wastewater treatment. Also, different types of nanosensors employed in the detection of metal ions with various interfaces have been highlighted.