Carbonaceous Quantum Dots and Their Application in Environmental Remediation

Abstract

Carbon quantum dots are sp2 /sp3 -hybridized carbon atoms with sizes ranging from 2-10nm. They are zero-dimensional florescent nanomaterials that are less toxic, more biocompatible and highly stable in nature. Carbon quantum dots have attracted the attention of many research groups due to their novel characteristics and have found several applications in industries. They are used in various scientific fields which include synthesis and design of inexpensive biological and chemical sensors. Carbon quantum dots have several uses in optical sensing, bio imaging, bio-sensing, optoelectronics photovoltaic and photocatalysis because of their superior electronic, optical, photocatalytic, up-conversion, photoluminescence and light harvesting properties. Using CQD, a cost-effective and environmentally friendly method of cleaning up environmental pollutants is introduced. They have lately been employed in remediation experiments in place of or together with metal semiconductors due to their optoelectronic features. Recently, the world has been facing serious threats due to environmental contamination of various kinds, which has become more serious due to lesser affordable means for treating it. Industrial waste, pesticides, heavy metal ions, pharmaceutical waste and sewage are some of the commonly observed water contaminants. Compared to the earlier studied forms of quantum dots, carbonaceous quantum dots are the most prevalent ones and can be a better option. The goal of this chapter is to explain the significance of carbonaceous quantum dots in environmental remediation. In addition, the advantages of carbonaceous quantum dots over conventional quantum dots, methods for synthesizing carbonaceous quantum dots (top down and bottom up), their functionalization or doping to improve their selectivity and sensitivity, their applications in various fields such as sensing, photocatalysis and biosensing have also been reviewed. By adding surface defects or interstitial states between electron holes, these alterations have a major impact on the optical characteristics of carbonaceous quantum dots. Additionally, the methods of removal of pollutants have also been explored by physical, chemical conventional and biological methods. Lastly, future perspectives and conclusion speculations have been considered.