Chemical Activation of Recycled Carbon Fibres for Application as Porous Adsorbents in Aqueous Media

The carbon fibre reinforced polymer (CFRP) industry has rapidly expanded over recent due to a range of benefits, including high mechanical strength and low weight. However, issues arise when the products reach their end-of-life (EoL). At present, pyrolysis is the only method for recycling CFRPs at scale. The process is still relatively new, resulting in stigma around the reapplication of recycled fibres within many industries due to the compromised mechanical stability. In order to increase the sustainability of the industry, alternative EoL pathways must be identified. Virgin carbon fibres (vCFs) have been successfully applied as adsorbents; however, there appears to be a gap in the literature when considering their recycled counterparts. In this study, chemical activation of industrial-grade recycled carbon fibres (rCFs) using NaOH has been investigated, together with vCF as proof of concept. The adsorption capacity of methylene blue (MB) was investigated to determine the degree of activation. The UV-visible spectrometry results indicated a maximum MB removal efficiency of 21.83 % and 21.80 % for activated-vCF (AvCF) and activated-rCF (ArCF), respectively; indicating that rCF are a promising precursor for applications as adsorbents in aqueous media, despite the higher levels of impurities when compared to the virgin counterpart.