A strategy for understanding the enhanced anaerobic co-digestion via dual-heteroatom doped bio-based carbon and its functional groups

Abstract

Heteroatom doping can fabricate functional groups on the surface of the bio-based carbon materials. In this work, two types of dual-heteroatom doped bio-based carbon (DHBC) were fabricated and used as accelerants to investigate the role of surface functional groups in anaerobic co-digestion (AcoD) system. N, P co-doped bio-based carbon (0.20 wt.%) achieved the highest methane production, cumulative biogas production, and total chemical oxygen demand degradation rate (350.21 mL/g VS, 526.77 mL/g VS, and 80.19%) during AcoD. The digestates exhibited excellent thermal stability (44.64%–45.28% for mass loss) and great potential (4.72%–4.88% for total nutrient content) as an alternative compound organic fertilizer. The notably improved AcoD performance was attributed to functional groups formed on the surface of DHBC, which facilitated electron exchange capacity and adsorption capability. A strategy to understand the enhanced methanogenesis in AcoD system based on the fabricated surface functional groups by heteroatom doping is proposed.