Textural characterisation of activated carbons obtained from poly(ethylene terephthalate) by carbon dioxide activation

Abstract

Polymer waste nowadays accounts for a large part of municipal solid waste and so poses a problem of considerable concern for the environment. In this study, it is reported that poly(ethylene terephthalate) pyrolysis is a valuable process with no residual solids, as all the products obtained are of potential use, i.e., energy from the gases produced (58%), terephthalic acid (approximately 20%), and a solid black residue (22%) which, when activated, shows interesting properties, making it useful as an adsorbent. Pyrolysis of raw PET was performed under nitrogen atmosphere, and ulterior activation was achieved at 925°C, with a flow rate of 10 mL min-1 of CO2, up to different burn-off degrees. Textural characterisation of the samples was carried out by measuring apparent density (mercury at 0.1 MPa), mercury porosimetry, and N2 and CO2 adsorption isotherms, at -196 and 0°C, respectively. The active carbons obtained were mainly microporous, with BET apparent surface areas of up to 2468 m2 g-1.