Investigating CO₂ sequestration via enhanced rock weathering: Effects of temperature and citric acid on dolomite and basalt

Enhanced rock weathering (ERW) is a promising approach for CO₂ sequestration, regulated by biotic factors such as root exudates and abiotic factors like temperature. Using dolomite and basalt, this study examined the CO 2 sequestration potential of ERW as affected by elevated temperature and citric acid, and the effects on soil C dynamics and heavy metal release in a 90-day leaching experiment. Dolomite showed a higher Mg-based CO₂ sequestration rate of 10.15-14.91 kg CO₂ t⁻ 1 yr⁻ 1 than basalt (2.88-11.85 kg CO₂ t⁻ 1 yr⁻ 1 ). While elevated temperature had no effect, citric acid significantly increased the Mg-based CO₂ sequestration rate, particularly for basalt by 224.5% compared to water. Dolomite and basalt increased leachate dissolved inorganic C (DIC) by 357.0% and 472.2%, respectively. Dolomite decreased soil dissolved organic C (DOC) by 47.3% and soil organic C (SOC) by 20.6%, while increasing soil inorganic C (SIC) by 806.2%. In contrast, basalt decreased soil DOC by 10.8%, increased soil DIC by 227.6%, and had no significant effect on SOC or SIC. Citric acid significantly stimulated the release of cobalt and strontium, and basalt addition increased soil cobalt and strontium concentrations, but these levels remained below safety thresholds. Both abiotic and biotic factors are essential to refine ERW strategies for climate change mitigation and sustainable soil management. • Dolomite surpassed basalt in CO 2 sequestration • Citric acid enhanced CO₂ sequestration more in basalt, with no temperature effect • Dolomite reduced soil DOC and SOC, likely due to a priming effect • High temperature increased organic C turnover with less impact on inorganic C • Citric acid enhanced Co/Sr release; basalt raised soil Co/Sr, but levels were safe