A Review of Functional Materials for Copper Ions Detection in Water

Abstract

Copper ions (Cu²⁺) are essential trace elements for living organisms; however, excessive concentrations in aquatic environments pose significant risks to human health and ecosystems. The increasing contamination of water resources by Cu²⁺ has created a strong demand for rapid, sensitive, and reliable detection technologies. This review comprehensively discusses recent advances in functional materials employed for Cu²⁺ detection in water, focusing on chitosan-based materials, carbon nanotubes (CNTs), cellulose-derived materials and salt-based sensing systems. The structural characteristics, sensing mechanisms, and performance of these materials are critically compared in terms of detection limits, sensitivity, adsorption capacity, and operational concentration ranges. Biopolymer-based materials such as chitosan and cellulose offer excellent biocompatibility and abundant functional groups for metal ion chelation, while CNTs provide superior electrical conductivity and large surface areas that enhance sensing efficiency. Salt-based chelators and optical sensing configurations further improve selectivity and detection sensitivity to the nanomolar level. Chemical modifications and composite formations are shown to significantly enhance material stability and sensing performance. Overall, this review highlights the potential of advanced functional materials for effective Cu²⁺ monitoring and provides insights into future developments for sustainable water quality assessment and environmental protection.