Improved carbon–mineral adsorbents derived from cross-linking carbon-bearing residues in spent palygorskite

Abstract

Spent natural palygorskite (Czerkawskiy District, Ukraine) after the use in paraffin purification was used here as the initial material for production of series of carbon–mineral adsorbents which were treated according to four procedures: hydrothermal modification; thermal modification; thermal modification with the addition of CCl 4; and porous structure modification. The physicochemical characteristics of the adsorbents were determined using nitrogen adsorption/desorption, XRD, TEM, and MS-TPD methods. The studied carbon–mineral adsorbents (CMA) contain 1.8–29.0% C w/w (samples based on the spent material) and 83.3–91.2% C w/w (for the reference carbon samples). The applied procedures allowed us to obtain adsorbents with the specific surface area larger than that of the starting palygorskite. As follows from the studies, during waste materials pyrolysis in the CCl 4 vapor atmosphere, there are parallel processes of organic substance carbonization, material carburization, and porous structure modification as well as sublimation or evaporation of metal chlorides contained in the mineral matrix and hydrogen chloride evolution.