Antioxidant depletion patterns of high-density polyethylene geomembranes in landfills under different exposure conditions.

The service life of high-density polyethylene (HDPE) geomembranes is directly determined by the landfill environment, and the antioxidant depletion stage is the first and most important stage of the HDPE geomembrane aging process. In this study, the antioxidant depletion stage was chosen to investigate the effects of different exposure environments on the HDPE geomembrane lifespan. The antioxidant depletion rate (ADR) and the antioxidant depletion time (ADT) of HDPE geomembranes under various exposure conditions were calculated based on the aging parameters obtained by fitting the collected reported data with the Arrhenius model. Also, the influence of exposure conditions on the HDPE geomembrane performance degradation was analyzed. The results showed that the aging method had the greatest effect on the antioxidant depletion period, while the HDPE geomembrane thickness had the least effect. The ADR sensitivity to brand/material, aging method, leachate components, and exposure medium decreased with increasing temperature; only the sensitivity to thickness showed a slight increasing tendency with increasing temperature. The ADTs of HDPE geomembranes under different exposure conditions ranged from 6 years to 900 years, indicating that the HDPE geomembranes can complete the service time of landfills under reasonable exposure conditions. This study provides a reliable methodological basis for the risk control and life prediction of HDPE geomembranes.