Thermochemical Characterization and Environmental Ash of COVID-19-Related Medical Waste Disposal

The extensive use of single-use personal protective equipment (PPE) during the COVID-19 pandemic has substantially increased the generation of plastic-rich medical waste, raising concerns regarding its safe thermal treatment and bottom ash management. This study investigates the thermochemical behavior of commonly used PPE items, nitrile gloves, polypropylene gowns, and polypropylene face masks, analyzed individually and in blended mixtures representative of hospital practice. Thermal degradation under combustion and pyrolysis conditions was characterized using TGA/DTG and DSC, while bottom ash was analyzed via SEM-EDX and ICP-OES. The environmental assessment performed in this study is intentionally limited in scope and focuses only on bottom-ash elemental composition and slagging tendency without evaluating leaching, emissions, or long-term stability. The results show that nitrile gloves exhibit multistage degradation and higher ash yields, whereas polypropylene-based PPE undergoes single-stage decomposition with distinct melting behavior. Synergistic interactions observed in blended waste streams lowered peak and burnout temperatures, indicating an enhanced combustion reactivity. Ash analyses identified Ca, Ti, and Zn as dominant constituents, with heavy-metal concentrations remaining below reported thresholds for nonhazardous waste classification. Within the restricted scope of ash chemistry and slagging performance, the findings suggest that cocombustion of mixed PPE waste may influence operational behavior during incineration; however, broader environmental implications require dedicated assessment through leaching, emissions monitoring, and mechanical performance testing.