VOC removal from automotive waste by supercritical CO₂ extraction

This study investigated the reduction of volatile organic compounds (VOCs) from waste polypropylene (PP) from automobile bumpers by supercritical carbon dioxide (scCO₂) extraction. The scCO₂ extraction was performed with varying temperatures, pressures, and times in the range of 313–353 K, 10–25 MPa, and 1–6 h, respectively. At 333 K, 25 MPa, and 6 h, highly efficient removal of xylene, styrene, and total VOCs were observed, with removal percentages of >98 %. Optimal condition for VOC removal using scCO₂ based on response surface methodology was determined to be 313 K, 10 MPa, and 2.17 h. No differences in size and color were observed in the scCO₂-treated PP pellets. Moreover, VOC removal using scCO₂ did not induce noticeable changes in the chemical and thermal properties of the treated PP samples. This result demonstrated that scCO₂ extraction is a promising method for the VOC removal from automobile plastic waste.