Artificial Humic Acid Mediated Carbon-Iron Coupling to Promote Carbon Sequestration

Yibo Lan; Shuang Gai; Kui Cheng; Zhuqing Liu; Markus Antonietti; Fan Yang

doi:10.34133/research.0308

Artificial Humic Acid Mediated Carbon-Iron Coupling to Promote Carbon Sequestration

Research (Wash D C). 2024 Feb 19:7:0308. doi: 10.34133/research.0308. eCollection 2024.

Authors

Yibo Lan^{1

2}, Shuang Gai^{1

2}, Kui Cheng^{2

3}, Zhuqing Liu^{1

2}, Markus Antonietti⁴, Fan Yang^{1

2}

Affiliations

¹ School of Water Conservancy and Civil Engineering, Northeast Agricultural University, Harbin 150030, China.
² International Cooperation Joint Laboratory of Health in Cold Region Black Soil Habitat of the Ministry of Education, Harbin 150030, China.
³ College of Engineering, Northeast Agricultural University, Harbin 150030, China.
⁴ Department of Colloid Chemistry, Max Planck Institute of Colloids and Interfaces, 14476 Potsdam, Germany.

Abstract

Fe (hydr)oxides have a substantial impact on the structure and stability of soil organic carbon (SOC) pools and also drive organic carbon turnover processes via reduction-oxidation reactions. Currently, many studies have paid much attention to organic matter-Fe mineral-microbial interactions on SOC turnover, while there is few research on how exogenous carbon addition abiotically regulates the intrinsic mechanisms of Fe-mediated organic carbon conversion. The study investigated the coupling process of artificial humic acid (A-HA) and Fe(hydr)oxide, the mechanism of inner-sphere ligands, and the capacity for carbon sequestration using transmission electron microscopy, thermogravimetric, x-ray photoelectron spectroscopy, and wet-chemical disposal. Furthermore, spherical aberration-corrected scanning transmission electron microscopy-electron energy loss spectroscopy and Mössbauer spectra have been carried out to demonstrate the spatial heterogeneity of A-HA/Fe (hydr)oxides and reveal the relationship between the increase in Fe-phase crystallinity and redox sensitivity and the accumulation of organic carbon. Additionally, the dynamics of soil structures on a microscale, distribution of carbon-iron microdomains, and the cementing-gluing effect can be observed in the constructing nonliving anthropogenic soils, confirming that the formation of stable aggregates is an effective approach to achieving organic carbon indirect protection. We propose that exogenous organic carbon inputs, specifically A-HA, could exert a substantial but hitherto unexplored effect on the geochemistry of iron-carbon turnover and sequestration in anoxic water/solid soils and sediments.