Enhancing Stable Electricity Generation and Assimilative Ammonium-N Removal in Photosynthetic Algae–Microbial Fuel Cells Using a Chlorella Biofilm-Loaded ZnO-NiO@rGO Carbon-Fiber Composite Cathode
Haiquan Zhan, Hong Wang, Yanzeng Li, Shiyu Liu +2
AI summary
82% confidenceThis study demonstrates that ZnO₀.₂-NiO@rGO-modified carbon-fiber cathodes substantially enhance voltage output and stabilize diurnal ammonium-nitrogen removal in photosynthetic algae–microbial fuel cells (PAMFCs) under continuous-flow, aeration-free operation. Modified cathodes achieved steady-state voltages of 0.34–0.38 V compared to 0.06–0.09 V for unmodified carbon felt, while reducing light–dark fluctuation in NH₄⁺–N removal efficiency by 32%. 18S rDNA profiling revealed that the engineered cathode interface selectively enriched a Chlorophyta-dominated biofilm (~80% relative abundance), linking interfacial conditions to stable community assembly and coupled electricity generation and nitrogen assimilation.
Generated by MESSAI extraction pipeline · review against source PDF
Representative MFC — matched on the paper’s system type only, not its reactor or geometry.
Reported parameters
No values extracted from this paper yet.
Open in lab for full controls, parameter editing, and template overlays.
Open in lab →What they did
- System
- MFC
What worked
No outcome metrics extracted yet.
Abstract
Photosynthetic algae–microbial fuel cells (PAMFCs) are attractive for energy-positive wastewater treatment and carbon mitigation. However, PAMFC performance under continuous flow is often constrained by limited cathodic electron-acceptor supply and unstable photosynthetic biofilms, while the extent to which cathode interfacial engineering can stabilize diurnal power output and assimilative NH4+–N removal remains unclear. In this study, the sponge-like and petal-like ZnO0.2-NiO@rGO-modified carbon fibers (ZnO0.2-NiO@rGO-pCFs and ZnO0.2-NiO@rGO-pCFp) and pre-fabricated carbon felt (pCF) were used as cathode materials to construct three sets of PAMFC systems. Under light–dark cycling, the engineered cathodes reached steady operation within about 6.5 d and increased the steady-state voltage to approximately 0.35 V, compared with approximately 0.08 V for pCF. Under continuous-flow conditions, cathodic NH4+–N removal exhibited a stable diurnal rhythm, with higher removal during illumination at about 43–51% than in the dark at about 29–30%, consistent with algal assimilation as the primary nitrogen sink, while cathode modification mainly improved the cathodic microenvironment and response stability. Compared with pCF, the ZnO0.2–NiO@rGO cathode enriched a more even, Chlorophyta-dominated algal biofilm with an approximate relative abundance of 80%, indicating that its selective interfacial environment favors biofilm stabilization and sustains in situ oxygen production and cathodic electron-acceptor supply. Consequently, the composite cathode enhanced voltage output and stabilized light-enhanced, assimilative NH4+–N removal under aeration-free operation, while establishing an interpretable link between electrochemical performance and 18S rDNA-derived community assembly features, thereby providing a low-cost cathode design basis for nitrogen removal in wastewater treatment.
Keywords
Identifiers
- Journal
- Water
- Year
- 2026