2026-10-13T10:22:53Z https://www.scidb.cn/oai

10.57760/sciencedb.43406 2026-07-20T16:21:02Z

2026-07-20 The performance improvement of soils by using the calcium carbonate slag-based biochar composite mineral materials and its mechanism doi:10.57760/sciencedb.43406 en Abstract: In this study, we respectively prepared two calcium carbonate slag-based biochar composite mineral materials (LDH-A and LDH-B) using raw materials of the industrial solid waste calcium carbonate slag and agricultural waste corn cob through the coprecipitation-hydrothermal and ball milling-hydrothermal methods, and compared the differences in effects of the two preparation processes on the structural properties of materials and the improvement effects of acidic soils, and clarified their functional mechanisms. The results show that both processes can be used to enable the in-situ loading of CaAl-LDH on corn cob biochar to form stable layered structures, but with distinct characteristics. The LDH-A has abundant oxygen-containing functional groups, uniform particle size, and strong colloidal stability. The LDH-B, after ball milling mechanochemical activation, has relatively high crystallinity, more ordered interlayer structure, and more excellent acid-base buffering capacity. Specifically, the entire preparation process of the LDH-B used only solid wastes (calcium carbonate slag and corn cob) without the need to add any external alkali source. Through the mechanochemical activation of ball milling, the in-situ growth and loading of the CaAl-LDH on the biochar surface are achieved. This process is green, low-cost, and easy to scale up for production. It overcomes the shortcomings of traditional LDH/biochar composites that rely on high-purity chemical reagents and complex procedures. Taking the acidic soil with initial pH value of 5.56 and organic carbon content of 35.92 g/kg in the Foshan area as research object, the 2.0% LDH-B had been put into the soil for 14 days. The pH value of the LDH-B treated soil was increased to 6.8 (11.7% increment). The improvement effect of the LDH-B is better than that of the LDH-A. This is mainly due to the synergistic buffering effect of Ca2+, OH− with H+ and CO23− in the LDH-B treated soil. In contrast, the organic carbon content of the 2.0% LDH-A treated soil is increased by 26.2% owing to abundant surface functional groups of the LDH-A. Pot experiments revealed that the LDH-B effectively promoted the crop growth and synergistically improved the soil microenvironment by leveraging the porous structure of biochar. Specifically, in the 2.0% LDH-B treated soil, the germination rate of water spinach reached 80.95% with its plant height of 12.1 cm, which are both significantly higher than those of the water spinach grew in untreated soil (with the germination rate of 76.19% and its plant height of 9.9 cm, respectively). In conclusion, the calcium carbonate slag-based biochar composite material prepared by using the ball milling-hydrothermal method has more prominent application advantages, which can be used to simultaneously realize the resource utilization of solid waste, improvement of acidic soil and promotion of crop growth, providing technical support for the green remediation of acidic cultivated land. Calcium carbonate slag; Layered double hydroxides; Biochar; improvement of acidic soil; Resource utilization Wu Gang Yao Fucheng Yang Zhao Hu Shuang Chen Meiqing Yuan Peng PUBLIC https://creativecommons.org/licenses/by-nc-nd/4.0/ dataset Science Data Bank