Waste-derived Fe-Co zeolitic imidazolate framework as an additive for enhanced methane production during anaerobic digestion of food waste
Year: 2026
Type: article
Abstract: The growing demand for renewable energy and sustainable waste management has increased interest in anaerobic digestion (AD) of food waste; however, limitations in substrate conversion and methane-production kinetics can restrict energy recovery. This study investigated waste-derived iron–cobalt zeolitic imidazolate framework (Fe-Co ZIF) as an additive for enhancing methane production during anaerobic co-digestion of food waste. Fe-Co ZIF was synthesized using iron recovered from waste iron filings and characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy and Brunauer–Emmett–Teller (BET) analysis. Batch digestion was conducted under mesophilic conditions using Fe-Co ZIF dosages of 20, 40, and 60 mg g -1 volatile solids (C20, C40, and C60), with an untreated control (C). Methane-production kinetics were evaluated using the Double-Gompertz model, while treatment effects were assessed using one-way ANOVA, effect size ( η 2 ), coefficient of variation and Tukey HSD multiple comparisons. Fe-Co ZIF produced a significant, non-linear dosage response. Cumulative methane production increased from 324.93 ± 13.46 mL g -1 VS in the control to 376.10 ± 10.59 and 384.80 ± 31.87 mL g -1 VS at C20 and C40, representing increases of 15.7% and 18.4%, respectively, whereas C60 produced only 329.00 ± 14.70 mL g -1 VS. The overall dosage effect on cumulative methane production was significant (F (3,8) = 7.624, p = 0.0099, η 2 = 0.741), with C20 and C40 significantly exceeding the control but remaining statistically comparable to each other. C20 exhibited the highest first-phase methane potential ( P 1 = 117.42 ± 4.85 mL g -1 VS) and maximum first- and second-phase production rates ( R 1 = 70.04 ± 6.15 and R 2 = 24.25 ± 2.14 mL g -1 VS Day -1 ), indicating superior kinetic acceleration and response consistency. Conversely, C40 produced the highest second-phase methane potential ( P 2 = 266.07 ± 6.08 mL g -1 VS) and total methane potential ( P total = 380.31 ± 15.31 mL g -1 VS), demonstrating greater ultimate methane-production capacity. Increasing the dosage to C60 provided no statistically supported methane-production advantage over the control while significantly prolonging the kinetic lag phases. Overall, the results identify 20–40 mg g -1 VS as the favorable Fe-Co ZIF dosage region, with C20 preferable for rapid and consistent methane generation and C40 advantageous for maximizing methane-production capacity. These findings demonstrate the potential of waste-derived Fe-Co ZIF for integrating iron-waste valorization with enhanced renewable methane recovery from food waste.
Source: Frontiers in Materials
Language: English
Field: Energy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $3,801
OpenAlex ID: W7225312966