1.School of Materials Science and Engineering,China University of Geosciences Beijing,Beijing ,China;2.School of Mathematics and Science,China University of Geosciences Beijing,Beijing ,China
Enhanced basalt weathering can release heavy metals and accumulate in soil, while the weathering products of basalt have a certain passivating effect on soil heavy metals. Therefore, investigating the bioavailability of heavy metals in soil during enhanced basalt weathering process is of great significance for the practical application of enhanced-basalt weathering carbon sequestration technology. This study used Tessier method, SEM, EDS, and other characterization methods to study the effect of enhanced basalt weathering on soil heavy metals. The results showed that basalt weathering increased soil pH, making heavy metals in soil more easily passivated. Most of the Cr and the Ni leached from basalt were fixed in residual form by basalt weathering products and soil clay minerals, and only a small amount of Cr and Ni flowed out with the effluent, causing no soil pollution. The new minerals formed by Ca, Mg, and Fe ions released by basalt dissolution during weathering, as well as other basalt weathering products, can transform heavy metals in soil into stable forms, reducing their bioavailability and achieving the goal of remediating soil heavy metal pollution.