A new method to obtain microporous carbons from PET: Characterisation by adsorption and molecular simulation

A new method for the preparation of activated carbons from poly(ethyleneterephthalate) (PET) has been developed. It is based on the basic hydrolysis of the PET wastes followed by heat treatment of the solid residue (terephthalate salt + base excess) under inert atmosphere. In this way, carbonisation and activation are combined on a single-step process which increases the carbon yield and reduces the evolution of volatile compounds and the temperature of treatment in comparison to the common PET carbonisation – CO2 activation method. The so prepared activated carbon samples present high adsorption capacity and a relatively homogenous and narrow microporosity which enlarges with treatment time, according to the data obtained from adsorption of different gases and organic vapours and by molecular simulation of adsorption. In fact, the textural characteristics of these samples are improved in relation to those produced by CO2 activation for the same time of treatment (besides the latter ones need to be activated at higher temperature). The new method proposed can be easily scaled-up and therefore can become an answer to the increasing environmental problems derived from the accumulation and elimination of PET residues from commercial plastic vessels.