Agricultural waste-derived Bio-C/MoS₂ anode enhances microbe-electrode interactions to reduce DOM toxicity in actual...

Environmental engineers urgently require efficient and practical solutions to reduce the toxicity of dissolved organic matter (DOM) in industrial wastewater to prevent detrimental effects on ecosystems. Herein, we developed a bioelectrochemical system utilizing an agricultural residue-derived biocarbon-based MoS₂ (Bio-C/MoS₂) anode, which successfully reduced DOM toxicity in actual industrial wastewater without incurring high costs or generating toxic byproducts. The bioreactor that employed the developed Bio-C/MoS₂ anode effectively reduced DOM toxicity by 63.1 % under an applied potential of 0.4 V, leading to an effluent toxicity of 5.6 % (determined by the zebrafish larvae malformation rate). Notably, DOM compounds with high double-bond equivalence (DBE) values were identified as the primary contributors to DOM toxicity using ultrahigh-resolution mass spectrometry. Further investigation into microbe-electrode interactions revealed that the Bio-C/MoS₂ anode reconstructed the microorganism-DOM interactions by affecting the composition of microbial communities that consume high-DBE DOM molecules, thereby reducing DOM toxicity. A life cycle assessment confirmed the economic advantages and environmental sustainability of the Bio-C/MoS₂ modification in practical applications. Overall, our study proposes a waste recycling method that effectively reduces DOM toxicity, offering a potential approach for practical applications in actual industrial wastewater treatment to purify effluent.