Optimization of anaerobic digestion process for methane production of J erusalem artichoke straw with mixed addition of Fe 3 O 4 and activated carbon

Abstract To explore the feasibility of enhancing anaerobic digestion (AD) of lignocellulosic wastes via the mixed addition of Fe 3 O 4 and activated carbon, Jerusalem artichoke straw (JAS) was used as the raw material, and the methane production process was optimized via single‐factor experiments combined with response surface methodology (RSM). The optimal process parameters derived from the RSM validation experiment were as follows: a total solid content of 5.27%, a mixing ratio of Fe 3 O 4 and activated carbon of 2.00:8.00, and an inoculation ratio of 2.52. Under these optimized conditions, the measured cumulative methane production calculated on the basis of volatile solid content reached 261.79 mL/g VS. The relative error between the measured value and the predicted value (265.66 mL/g VS) was less than 5%, confirming the validity of the established model. This mixed addition treatment significantly enhanced the methane‐producing capacity of JAS under optimized conditions ( p = 0.014 <0.05), and its performance was 34.77% higher than that of the control group (188.82 mL/g VS), which was comparable to conventional chemical pretreatment methods. Moreover, it increased the acetic acid content and reduced the accumulation of propionic acid and butyric acid. Furthermore, the optimized mixed addition treatment also exhibited favorable economic benefits, rendering it a relatively suitable mixed addition scheme for the AD of JAS. These findings show that the mixed addition of Fe 3 O 4 and activated carbon enables efficient biomethane production and the environmentally friendly treatment of lignocellulosic waste.