Abstract
Co-gasifying agricultural waste with polymer-rich single-use trash may boost thermochemical waste valorization. Combination thermal behavior is linear additive. Heat rates of 10, 20, and 30 °C min−1 were assessed using thermogravimetric data on coffee husk, face-mask waste, and CH/M blends (75/25, 50/50). Parent TG data indicated additive baselines, and non-additivity was assessed over 50-750 °C. All feedstocks' principal DTG peaks rose with heating rate in trials. At 10-30 °C/min, CH100 DTG peaks shifted from 314.4 to 336.3 °C and M100 from 403.7 to 432.7. All three combinations lose mass more than expected in most conversion ranges. The highest and longest-lasting non-additive reaction was CH50M50. At 50-750 °C, mean interaction deviation (experimental residual mass minus additive prediction) was -14.31, -13.43, and -12.93 percentage points at 10, 20, and 30 °C min⁻¹ Residual-mass deviations were -31.36%, -30.38%, and -28.98% at 750°C. Negative values result in reduced residual mass and increased apparent conversion at 10, 20, and 30 °C min−1 compared to additive baselines. CH50M50 residual deviations were -31.36, -30.38, and -28.98% at 750 °C. CH/mask co-processing is non-additive and not a thermal program artifact because all three experimental heating speeds interact negatively. Multiple screening rates co-value reactor-scale CH/mask waste.