Decontamination of recycled LDPE using different washing methods

Post-consumer low density polyethylene samples were analysed for PAHs, PCDD/Fs and dioxin-like PCBs con -tent. Subsequently, various treatments were applied to determine a process capable of decontaminating the plastic samples: extraction with polyethylene glycol at different temperatures with and without agitation; extraction using subcritical and hot water at different temperatures in a basic medium; compound degradation by ultraviolet radiation; and compound degradation by advanced oxidation processes using H2O2. The most effective treatment was extraction with polyethylene glycol (agitated) at 120 ?, reducing contamination by 89%, 85% and 95% of PAHs, PCDD/Fs, and dioxin-like PCBs, respectively. The least effective treatments (subcritical and hot water), maximum reductions of 47% and 19% of PAHs were obtained for the temperatures of 160 ? and 90 ?. UV oxidation increased the toxic equivalency of the samples (calculated using the toxicity equivalency factors) by up to 1400%, through the co-formation of the most toxic congeners, e.g., the non-ortho PCBs

Automated summary

The study analyzed post-consumer low-density polyethylene samples for PAHs, PCDD/Fs, and dioxin-like PCBs content. Different treatments were conducted, including extraction with polyethylene glycol at different temperatures with and without agitation, extraction using subcritical and hot water in a basic medium, compound degradation by ultraviolet radiation, and compound degradation by advanced oxidation processes using H2O2. The most effective treatment was extraction with polyethylene glycol (agitated) at 120℃, reducing contamination by 89%, 85%, and 95% of PAHs, PCDD/Fs, and dioxin-like PCBs, respectively. UV oxidation increased the toxic equivalency of the samples by up to 1400%.