Improvement of the adsorption properties of carbon black granules by means of plasma enhanced-chemical vapour deposition with acrylic acid vapours

Carbon black granules were coated by thin polymers in radio frequency glow discharges fed with acrylic acid/argon mixtures at different input powers, in order to improve the adsorption ability of basic compounds in the liquid and gas phases.The treated surfaces were characterized by X-ray photoelectron spectroscopy analyses and water contact angle measurements, performed immediately after the plasma treatment, after ageing in water and in air, and after heating up to 150 °C.The adsorption ability of basic compounds in the liquid and gas phases was evaluated with Boehm titrations and ammonia adsorption, respectively.Scanning electron microscopy observations and Brunauer, Emmett, Teller specific surface area measurements were performed to evaluate the morphological changes induced by the plasma treatments on the carbon black granule surface.The results show that the plasma treatments significantly improve the absorption ability of carbon black mainly for grafting of carboxylic groups and not for surface morphological modifications.

In this work, for the first time, the plasma enhanced-chemical vapour deposition (PE-CVD) technique has been employed in order to improve the adsorption ability of granular carbon black granules. In specific way, the carbonaceous substrates have been coated with acrylic acid films deposited using a home-made rotating, low pressure plasma reactor able to ensure an homogeneous treatment of each granule. In this way, it has been possible to increase of about 70% the adsorption of basic compounds in liquid and in gas/vapour phases.The treated surfaces were characterized by X-ray photoelectron spectroscopy analyses and water contact angle measurements, performed immediately after the plasma treatment, after ageing in water and in air, and after heating up to 150 °C. The adsorption ability of basic compounds in the liquid and gas phases was evaluated with Boehm titrations and ammonia adsorption, respectively.Scanning electron microscopy observations and Brunauer, Emmett, Teller specific surface area measurements were, finally, performed to evaluate the morphological changes induced by the plasma treatments on the carbon black granule surface.Figure optionsDownload as PowerPoint slideResearch highlights
► Radio Frequencies glow discharges fed with acrylic acid vapours can be employed to cover carbon black granules.
► Plasma coated carbon black granules show acid surface properties.
► Carbon black granules surface plasma modified can be used as adsorbents for basic compounds in liquid and in gas phases.
► Employing this surface modification technique it is possible to improve of about 70% the adsorption properties of granular carbon black.