Catalytic Combo Converts CO2 to Solid Carbon Nanofibers

[OKIsItJustMe]

5. There is a risk associated with carbon nanofibers (comparable to asbestos fibers which are also natural)

https://doi.org/10.3390/nano11030745

Occupational Exposure to Carbon Nanotubes and Carbon Nanofibres: More Than a Cobweb

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Nanomaterials 2021, 11(3), 745; https://doi.org/10.3390/nano11030745
Submission received: 11 February 2021 / Revised: 11 March 2021 / Accepted: 13 March 2021 / Published: 16 March 2021
(This article belongs to the Special Issue Engineered Nanomaterials Exposure and Risk Assessment: Occupational Health and Safety)

Abstract

Carbon nanotubes (CNTs) and carbon nanofibers (CNFs) are erroneously considered as singular material entities. Instead, they should be regarded as a heterogeneous class of materials bearing different properties eliciting particular biological outcomes both in vitro and in vivo. Given the pace at which the industrial production of CNTs/CNFs is increasing, it is becoming of utmost importance to acquire comprehensive knowledge regarding their biological activity and their hazardous effects in humans. Animal studies carried out by inhalation showed that some CNTs/CNFs species can cause deleterious effects such as inflammation and lung tissue remodeling. Their physico-chemical properties, biological behavior and biopersistence make them similar to asbestos fibers. Human studies suggest some mild effects in workers handling CNTs/CNFs. However, owing to their cross-sectional design, researchers have been as yet unable to firmly demonstrate a causal relationship between such an exposure and the observed effects. Estimation of acceptable exposure levels should warrant a proper risk management. The aim of this review is to challenge the conception of CNTs/CNFs as a single, unified material entity and prompt the establishment of standardized hazard and exposure assessment methodologies able to properly feed risk assessment and management frameworks.

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