Engineered Carbon Nanotubes: Review on the Role of Surface Chemistry, Mechanistic Features, and Toxicology in the Adsorptive Removal of Aquatic Pollutants

The advent of nanotechnology has led to the development of new nanomaterials with enriched material properties over the conventional. These nanomaterials find wide application in numerous fields including environmental predominantly on water purification. Carbon nanotubes (CNT) are one among the nanomaterials widely employed for such application. Therefore, the present review emphasizes on the exceptional abilities of CNT especially in the removal of organics and inorganics from aquatic streams. Though numerous reviews were published in this subject most of them focused on the synthesis and specific applications. The authors learned that there is a wider gap on the review that presents the mechanistic features like the development of active sites, the effect of curvature, inclusion of heteroatoms, methods for the enhancement of affinity and selectivity through functionalization, the introduction of defects and the chemistry involved in their interaction with various category of pollutants. Hence, the present review delivers a clear understanding of the above-said factors in a comprehensive way. The article explicits on the various surface modification techniques (i.e covalent, non-covalent, defect and endohedral) along with their effects on the sorption efficiency. Further, the review also provides a clear picture of the toxicological aspects of the CNT. The authors strongly believe that the present review will aid in the understanding and design of multifunctional CNT towards environmental application in a comprehensive manner.