Review on g-C3N4 Based Fluorescence Chemical Sensor for Detection of Heavy Metal Ions

Abstract

Recently, among many kinds of chemo sensors, the development of fluorescent chemo sensors for the sensing of environmentally toxic heavy metal ions has drawn continuous interest in fields of chemistry, materials, biological and environmental sciences due to the low cost, simple operation, high sensitivity and specificity, real-time monitoring and short response time. Upon interactions with the metal ions, the fluorescence intensity and/or fluorescence band shift of the chemosensory change and the metal ions may be detected qualitatively and quantitatively. Many methods employ techniques related to metal ion sensing. The quenching photoluminescence of carbon-based nanodots has been focused on monitoring metal ions. The employ g-C3N4 as fluorescence chemical sensors for heavy metal ions detection has caused increased attention largely due to its fluorescent property. Several groups have demonstrated the use of different g-C3N4 nanostructures for fluorescent metal ions sensing. Considering the properties of present chromogenic/fluorescent receptors, it seems that nanostructured g-C3N4 would be a promising alternative. The electronic structure of g-C3N4 is adjustable by coupling events of protons or metals to the surface. Therefore, the strong coordination of the nitrogen sites of g-C3N4 to metal ions, causes fluorescence quenching via photoinduced electron transfer and static quenching leading to the qualitative and quantitative detection of metal ions. It has been brought into some brilliant applications, Specially for detection of Cu2+, Fe3+, Hg+2 and Ag+ has been developed based on the fluorescence quenching because of the photoinduced electron transfer (PET) from g-C3N4 to metal ion and also it is best alternate than other material for detection of metal ion because of its low-cost, good biocompatibility, high quantum yield, excellent stability and non-toxicity.