Performance evaluation of three kinetic models on biomethane yield of nano-additive pretreated Xyris capensis

Kinetic modeling of the anaerobic digestion process is crucial to biomethane optimization. This study investigates the performance of three kinetic models, Gompertz, modified Gompertz, and Schnute, on fitting the biomethane production process of nano-additive pretreated Xyris capensis. The cumulative biomethane yield of Fe₃O₄, CuO, MgO, ZnO nano-additives, and untreated Xyris capensis was fitted with the selected kinetic models, and the models' performance was evaluated and compared. It was discovered that all the models can fit the cumulative biomethane yield. Still, the modified Gompertz model produced the best fit among the three models with a correlation coefficient (R²) of 0.9959 and an Akaike information criterion (AIC) value of 170.51. It was observed from the study that pretreatment conditions have a significant influence on kinetic model performance, and the best performance is recorded from the untreated substrate across all the models. This information can be used for biomethane optimization at the commercial scale.