Green Oxidation of Carbon Black by Dry Ball Milling

Abstract

A sustainable and green method is presented in this paper to produce highly oxidized carbon black using dry ball milling. The mechanical energy by colliding milling balls is able to easily break and build chemical bonds providing new oxygenated functional groups. The reaction is performed in the presence of air and in solvent-free conditions achieving, for the first time, a high degree of functionalization comparable to that obtained under harsh conventional conditions. With different milling times, it is possible to control the degree of oxidation. The procedure is environmentally friendly, respecting important green metrics, no solvent or additional reagent is required, and the product can be collected without any assistance from a solvent.

Sustainable functionalization of carbon black via dry ball milling

“…As a result of the exfoliation and fragmentation of carbon materials conducted under solvent-free conditions, oxygen functionalities can be introduced into the carbon surface. 34 Although the degree of oxidation is comparable to that obtained by Hummers, the functional groups' nature is deeply different. Specifically, unsaturated lactones and/or ketones as well as ethers, are obtained by ball milling procedures, while epoxides, ethers, and carboxyl groups are prevalent by the Hummers method.…”

“…To confirm the ionic nature of the adduct, an additional test was performed by using oxidized carbon black obtained by ball milling oxidation, which is characterized by the presence of unsaturated ketones and lactones and the absence of carboxyl groups. 34…”

“…To confirm the ionic nature of the adduct, an additional test was performed by using oxidized carbon black obtained by ball milling oxidation, which is characterized by the presence of unsaturated ketones and lactones and the absence of carboxyl groups. 34 The reaction was carried out under the optimized conditions, but no functionalization occurred showing the necessary contribution of the carboxyl group to promote the ionic exchange.…”

Eco-friendly one-shot approach for producing a functionalized nano-torrefied biomass: a new application of ball milling technology

“…In particular, harsh conditions like those required from the Hummers oxidation were needed to provide the carboxyl functionalities essential for the cation exchange. 27 Conversely, in the presence of a starting material such as B1, the extensive presence of hydroxyl groups suitable for cation exchange, could avoid the additional step of oxidation providing a completely green functionalization. Then, to verify the ability of B1 to be ionically functionalized by using the mechanochemical approach, the first reaction was performed in the conditions already optimized for oxidized carbon black.…”

“…An easy chemical modification on carbon surface was recently reported by using an eco-friendly procedure, where the ability of carbon black to form an ionic bond with quaternary phosphonium salt using a dry planetary ball milling was investigated. 27 The reaction takes place in 30 minutes without solvent and any additional reagent, through the breaking or building of chemical bonds by applying both impact and shear forces to particles that collide with the milling balls. First elastic forces and then irreversible plastic deformations generate new surfaces of the reactant easier to contact and react.…”