Introduction of Basic Functionalities on the Surface of Granular Adsorbers by Low Pressure Plasma Processes

Low pressure plasma, generated in a radio frequency reactor under rotation, was utilized to modify the ability of granular substrates to adsorb volatile acid compounds. Carbon black granules were treated with NH3 or allylamine containing feeds, while sepiolite granules were processed only in allylamine fed discharges. The chemical modifications induced by plasma treatments were evaluated by means of X-ray photoelectron spectroscopy studies and water contact angle measurements, while scanning electron microscope and Brunauer, Emmet, Teller analyses were performed to study the surface morphological changes caused by plasma processes. The ability of the treated materials to adsorb acids, in gas or vapour phase, was estimated with hydrochloric, acetic and propanoic acid, employing a home-made test system. The results show that the optimized plasma treatments are able to improve the adsorption ability of carbon black and sepiolite granules for the three acids investigated. re la tiv e ad so rb ed e qu iv al en ts % /se pi ol ite g HCl CH3CO2H CH3CH2CO2H