School of Civil Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China; Shaanxi Key Laboratory of Geotechnical and Underground Space Engineering (XAUAT), Xi'an, 710055, China.
Environ Pollut. 2023 Apr 1;322:121218. doi: 10.1016/j.envpol.2023.121218. Epub 2023 Feb 8.
Lead (Pb) metal accumulation in surrounding environments can cause serious threats to human health, causing liver and kidney function damage. This work explored the potential of applying the MICP technology to remediate Pb-rich water bodies and Pb-contaminated loess soil sites. In the test tube experiments, the Pb immobilization efficiency of above 85% is attained through PbCO and Pb(CO)(OH) precipitation. Notwithstanding that, in the loess soil column tests, the Pb immobilization efficiency decreases with the increase in depth and could be as low as approximately 40% in the deep ground. PbCO and Pb(CO)(OH) precipitation has not been detected as the majority of Pb combines with -OH (hydroxyl group) when subjected to 500 mg/kg Pb. The alkaline front promotes the chemisorption of Pb with CO reducing the depletion of quartz mineral close to the surface. However, OH is in shortage in the deep ground retarding the Pb immobilization. The Pb immobilization efficiency thus decreases with the increase in depth. Quartz and albite minerals, when subjected to 16,000 mg/kg Pb, appear not to intervene in the chemisorption with Pb where the chemisorption of Pb with CO plays a major role in the Pb immobilization. Compared to the nanoscale urease applied to the enzyme-induced carbonate precipitation (EICP) technology, the micrometer scale ureolytic bacteria penetrate into the deep ground with difficulty. The 'size' issue remains to be addressed in near future.
铅（Pb）金属在周围环境中的积累会对人类健康造成严重威胁，导致肝肾功能受损。本工作探索了应用 MICP 技术修复富含 Pb 的水体和 Pb 污染黄土土壤场地的潜力。在试管实验中，通过 PbCO 和 Pb(CO)(OH)沉淀达到了超过 85%的 Pb 固定效率。然而，在黄土土壤柱测试中，Pb 固定效率随着深度的增加而降低，在深部地面时，固定效率可能低至约 40%。PbCO 和 Pb(CO)(OH)沉淀并未被检测到，因为大部分 Pb 与-OH（羟基）结合，当受到 500mg/kg Pb 的作用时。碱性前缘促进了 Pb 与 CO 的化学吸附，减少了靠近表面的石英矿物的消耗。然而，深部地面的 OH 短缺会阻碍 Pb 的固定。因此，Pb 固定效率随着深度的增加而降低。当受到 16000mg/kg Pb 的作用时，石英和钠长石矿物似乎不会干预与 Pb 的化学吸附，其中 Pb 与 CO 的化学吸附在 Pb 固定中起主要作用。与应用于酶诱导碳酸沉淀（EICP）技术的纳米级脲酶相比，微米级脲酶细菌难以渗透到深部地面。“尺寸”问题仍有待解决。
