Influence of Oxygen-Containing Functional Groups on the Environmental Properties, Transformations, and Toxicity of Carbon Nanotubes

Abstract

Carbon nanotubes (CNTs) have unique physical and chemical properties that drive their use in a variety of commercial and industrial applications. CNTs are commonly oxidized prior to their use to enhance dispersion in polar solvents by deliberately grafting oxygen-containing functional groups onto CNT surfaces. In addition, CNT surface oxides can be unintentionally formed or modified after CNTs are released into the environment through exposure to reactive oxygen species and/or ultraviolet irradiation. Consequently, it is important to understand the impact of CNT surface oxidation on the environmental fate, transport, and toxicity of CNTs. In this review, we describe the specific role of oxygen-containing functional groups on the important environmental behaviors of CNTs in aqueous media (e.g., colloidal stability, adsorption, and photochemistry) as well as their biological impact. We place special emphasis on the value of systematically varying and quantifying surface oxides as a route to identifying quantitative structure−property relationships. The role of oxygen-containing functional groups in regulating the efficacy of CNT-enabled water treatment technologies and the influence of surface oxides on other carbon-based nanomaterials are also evaluated and discussed.

Recent advancements in transparent carbon nanotube films: chemistry and imminent challenges

“…One more significant correlation to estimate is the outcome of surface oxygen at the sensitivity of CNTs over microbial biodegradation, as fluctuations during the rate of degeneration will manage the chance of susceptibility to different bodies. The cytotoxicity of CNTs united among the disobedience of their aromatic composition induces their regression through microorganisms to be usually delayed or missing, while surface oxidation or disclosure to combined culture bacteria has been determined to improve enzymatic degeneration of CNTs [77].…”

Recent Advances in Functional Carbon Quantum Dots for Antitumour

“…13 Although these nanomaterials are mainly composed of the same element, carbon, they have different functions and sizes due to their different structures, which ensures that they have different but extraordinary properties. Carbon nanomaterials have been widely reported and include carbon nanotubes (CNTs), 14 carbon fibres (CFs) 15 and carbon quantum dots (CQDs). 16 CNTs, also known as bucky tubes, are one-dimensional quantum materials with a unique structure of coaxial circular tubes.…”

Synthesis of Phosphonated Carbon Nanotubes: New Insight into Carbon Nanotubes Functionalization

“…One key area of research deals with the introduction of different functional groups onto the surface of CNTs. The most common are definitely oxygen functional groups (e.g., hydroxyl, carboxyl, carbonyl); however, many examples of CNTs with nitrogen (e.g., amine, amide) and sulfur-containing (e.g., thiol, sulfonic) functional groups can also be found in the literature [ 15 , 16 , 17 , 18 ]. Contrary to the examples mentioned above, phosphorus-containing groups, especially those with a phosphorus atom attached directly to the carbon skeleton, are rarely reported.…”