Recent Advancement in the Development of Detection and Removal of Heavy Metal Ions by Deep Eutectic Solvents: A Review

: Heavy metal pollution is one of the most serious environmental problems, because of the non-degradable nature of heavy metals and their accumulation in the food chain, which poses a severe threat to the environment and human health even at low concentrations. Most of these metal ions can coordinate with biological molecules and disturb their function. Exposure to heavy metals can cause different health threats such as endothelial dysfunction, allergy, infant mortality, cancer, neurological diseases, respiratory diseases, oxidative stress, cardiovascular disorders and kidney diseases. Therefore the detection and removal of these toxic species are very important. Deep eutectic solvents (DESs) are green solvents and have excellent applications in many fields. They contain nonsymmetrical ions that have low lattice energy, low vapor pressure, dipolar nature, nonflammability, low volatility, low melting points, excellent thermal and chemical stability and high solubility. DESs are also better in terms of the availability of raw materials, easy synthetic procedure, low cost of their starting materials and their easy storage. DESs have an excellent ability for the detection and removal of heavy metal ions. In this review, we discussed various DES-based spectrophotometric and fluorimetric chemosensors for the detection of heavy metal ions in different matrixes. Additionally, we have also explored the capabilities of different DESs in removing heavy metals.