Texture development during activation of carbonaceous materials derived from polyethyleneterephthalate

摘要

Polyethyleneterephthalate, PET, has become one of the major post-consumer plastic wastes. PET products present a problemrnof considerable concern due to the huge amount of solid waste produced. The disposal of this waste together with its low bio-rnand photo-degradability, represents a serious challenge for industrial countries worldwide. Pyrolysis could be an alternativernand interesting route for processing of PET wastes, due to the potential uses of different products: energy recovery from thernpyrolysis gases (58% yield in this work), recuperation of terephthalic acid (20%), and a solid residue (22%) which showed arnhigh texture development after activation. Pyrolysis of raw PET was performed in a quartz reactor (I.d. 35 mm) underrnnitrogen atmosphere. Ulterior activation was carried out at an optimised temperature of 925 ℃, with a flow rate of 10 mLrnmin-1 of CO2. A series of chars with different burn-off degrees was obtained. Textural characterisation of the samples wasrncarried out by performing N2 and CO2 adsorption isotherms at –196 and 0 ℃, respectively. The obtained active carbons werernmainly microporous, with low meso and macroporosity, and with BET apparent surface areas of up to 2500 m2g-1. Inrnaddition, the reactivity of the samples in air was determined by non-isothermal tests in a thermogravimetric analyser. It wasrnobserved that the activation energy remained constant with the burn-off degree of the samples.