Synthetic Approaches, Modification Strategies and the Application of Quantum Dots in the Sensing of Priority Pollutants

Abstract

Polycyclic aromatic hydrocarbons (PAHs) and nitro-aromatic compounds (NACs) are two classifications of environmental pollutants that have become a source of health concerns. As a result, there have been several efforts towards the development of analytical methods that are efficient and affordable that can sense these pollutants. In recent decades, a wide range of techniques has been developed for the detection of pollutants present in the environment. Among these different techniques, the use of semiconductor nanomaterials, also known as quantum dots, has continued to gain more attention in sensing because of the optical properties that make them useful in the identification and differentiation of pollutants in water bodies. Reported studies have shown great improvement in the sensing of these pollutants. This review article starts with an introduction on two types of organic pollutants, namely polycyclic aromatic hydrocarbons and nitro-aromatic explosives. This is then followed by different quantum dots used in sensing applications. Then, a detailed discussion on different groups of quantum dots, such as carbon-based quantum dots, binary and ternary quantum dots and quantum dot composites, and their application in the sensing of organic pollutants is presented. Different studies on the comparison of water-soluble quantum dots and organic-soluble quantum dots of a fluorescence sensing mechanism are reviewed. Then, different approaches on the improvement of their sensitivity and selectivity in addition to challenges associated with some of these approaches are also discussed. The review is concluded by looking at different mechanisms in the sensing of polycyclic aromatic hydrocarbons and nitro-aromatic compounds.

High Quantum Yield Nitrogen-Doped Carbon Quantum Dot-Based Fluorescent Probes for Selective Sensing of 2,4,6-Trinitrotoluene

“…7 Because of its serious toxicity to both humans and the environment, TNT is included in the US Environmental Protection Agency's (EPA) priority pollutants list. 8 Various methods such as high-performance liquid chromatography (HPLC), 9 liquid chromatography−mass spectrometry (LC− MS), 10 gas chromatography−mass spectrometry (GC−MS), 11 and surface plasmon resonance sensing 12 have been developed for the determination of TNT. Although these methods have high reliability and accuracy, they have disadvantages such as process complexity, preliminary sample preparation, the need for qualified personnel, and high-cost instrumentation.…”

“…As a result of this contamination, TNT residues can cause many health problems, especially anemia and abnormal liver functions . Because of its serious toxicity to both humans and the environment, TNT is included in the US Environmental Protection Agency’s (EPA) priority pollutants list . Various methods such as high-performance liquid chromatography (HPLC), liquid chromatography–mass spectrometry (LC–MS), gas chromatography–mass spectrometry (GC–MS), and surface plasmon resonance sensing have been developed for the determination of TNT.…”

Quantum dots: a tool for the detection of explosives/nitro derivatives

“…9 Due to the toxicity of TNT to both humans and the environment, the US Environmental Protection Agency (EPA) considered TNT in the priority pollutants list. 10…”

“…9 Due to the toxicity of TNT to both humans and the environment, the US Environmental Protection Agency (EPA) considered TNT in the priority pollutants list. 10 In light of this, chemical sensing of these nitro derivatives has been a great demand in society due to environmental concerns and they are extensively used as explosives. Various methods have been used for the sensing of these nitro derivatives, including chromatographic separation techniques, 11 trained canine teams, 12 mass spectrometry, 13 infrared absorption spectroscopy, 14 surface-enhanced Raman spectroscopy, 15,16 X-ray imaging, 17 thermal neutron analysis, 18 electrochemical procedures, 19 and ion mobility spectrometry (IMS).…”

Carbon dots and miniaturizing fabrication of portable carbon dot-based devices for bioimaging, biosensing, heavy metal detection and drug delivery applications

“…The inherent toxicity of cadmium might cause the deterioration of heavy metal pollution. 1 In 2004, a fluorescent nanomaterial from the single-wall carbon nanotubes from arc-discharge soot was accidentally discovered during the purification and separation processes. 2 This serendipitous discovery of CDs has triggered the following studies regarding the fluorescence properties possessed by the CDs.…”