Catalytic Hydrothermal Degradation of Carbon Reinforced Plastic Wastes for Carbon Fibre and Chemical Feedstock Recovery

• Published in: Waste and biomass valorization 2013-03, Vol.4 (1), p.87-93
• Main Authors: Onwudili, Jude A., Yildirir, Eyup, Williams, Paul T.
• Format: Article
• Language: English
• Subjects: Engineering; Environment; Environmental Engineering/Biotechnology; Industrial Pollution Prevention; Original Paper; Renewable and Green Energy; Waste Management/Waste Technology
• ISSN: 1877-2641; 1877-265X
• DOI: 10.1007/s12649-013-9204-4

Recovery of carbon fibre and chemical feedstock via catalytic hydrothermal degradation of waste carbon fibre reinforced plastic (CFRP) sample was investigated in a stainless steel batch reactor between 400 and 420 °C and pressures of 20 and 25 MPa, respectively. Sodium hydroxide and potassium hydroxide were used as catalysts/additives. Using supercritical water alone, a maximum of 54.5 wt% of resin was removed from the CFRP at 420 °C, but with high recovery of phenol in the liquid residual. The presence of NaOH or KOH alone in water led to up to 81 wt% resin removal, even at short reaction times. Extracts from the liquid residual contained phenol and aniline as the major components; thus representing a potential for monomer recovery. For instance, the use of KOH alone gave phenol yield of 377 mg/(g resin) and aniline yield of 112 mg/(g resin). In addition, the presence of the alkalis led to the recovery of carbon fibres with very good mechanical properties.