Prompt Description

Create a visually compelling graphical abstract illustrating a two-stage electro-assisted dark fermentation-microbial electrolysis cell (DF-MEC) system for biohydrogen production. Employ flat scientific icons, a soft color palette, prominent arrows, and minimal text. Panel 1 – Feedstock (left): Icons: Food waste and swine manure. Arrow leading to a mixed tank. Text (small): Carbon-rich + Nitrogen-rich → Balanced feed Tags: Self-pH regulation | Optimized C/N ratio | Electron-rich Side icons: • Heat treatment: 80 °C, 20 min • Suppressed methanogenesis (crossed-out CH₄ icon) Panel 2 – Stage I: Electro-Assisted Dark Fermentation (center): Single fermenter vessel containing microorganisms in broth. Electrodes inserted: • Carbon felt bioanode • Stainless steel biocathode Connected to an external power supply. Illustrate electron flow (e⁻): anode → circuit → cathode, with electrons interacting with microbes. Side icons: • Hydraulic Retention Time (HRT) control Text (short): Electro-DF | Redox control Inset zoom 1 (cell level): Microbial cell diagram showing: NADH/NAD⁺ ratio increase → Hydrogenase activity increase → H₂ production increase Arrow from anode to cell, labeled "Low ORP" Fade out lactate/ethanol icons (representing reduced production). Emphasize enhanced extracellular electron transfer (EET). Output arrow: Acetate-rich effluent