College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China.
College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China.
Sci Total Environ. 2018 Sep 1;635:92-99. doi: 10.1016/j.scitotenv.2018.04.119. Epub 2018 Apr 13.
The remediation of heavy metal-contaminated soils is a great challenge for global environmental sciences and engineering. To control the ecological risks of heavy metal-contaminated soil more effectively, the present study focused on the combination of soil washing (with FeCl) and in situ immobilization (with lime, biochar, and black carbon). The results showed that the removal rate of Cd, Pb, Zn, and Cu was 62.9%, 52.1%, 30.0%, and 16.7%, respectively, when washed with FeCl. After the combined remediation (immobilization with 1% (w/w) lime), the contaminated soils showed 36.5%, 73.6%, 70.9%, and 53.4% reductions in the bioavailability of Cd, Cu, Pb, and Zn (extracted with 0.11M acetic acid), respectively, than those of the soils washed with FeCl only. However, the immobilization with 1% (w/w) biochar or 1% (w/w) carbon black after washing exhibited low effects on stabilizing the metals. The differences in effects between the immobilization with lime, biochar, and carbon black indicated that the soil pH had a significant influence on the lability of heavy metals during the combined remediation process. The activity of the soil enzymes (urease, sucrase, and catalase) showed that the addition of all the materials, including lime, biochar, and carbon black, exhibited positive effects on microbial remediation after soil washing. Furthermore, lime was the most effective material, indicating that low soil pH and high acid-soluble metal concentrations might restrain the activity of soil enzymes. Soil pH and nutrition were the major considerations for microbial remediation during the combined remediation. These findings suggest that the combination of soil washing and in situ immobilization is an effective method to amend the soils contaminated with multiple heavy metals.
受重金属污染土壤的修复是全球环境科学与工程面临的重大挑战。为了更有效地控制重金属污染土壤的生态风险，本研究聚焦于土壤淋洗（FeCl）与原位固定化（石灰、生物炭和黑炭）的联合修复。结果表明，用 FeCl 淋洗时，Cd、Pb、Zn 和 Cu 的去除率分别为 62.9%、52.1%、30.0%和 16.7%。经联合修复（用 1%（w/w）石灰固定化）后，与仅用 FeCl 淋洗的污染土壤相比，用 0.11M 乙酸提取的 Cd、Cu、Pb 和 Zn 的生物可利用性分别降低了 36.5%、73.6%、70.9%和 53.4%。然而，淋洗后用 1%（w/w）生物炭或 1%（w/w）炭黑固定化对稳定金属的效果较低。石灰、生物炭和炭黑固定化效果的差异表明，在联合修复过程中，土壤 pH 值对重金属的变异性有显著影响。土壤酶（脲酶、蔗糖酶和过氧化氢酶）的活性表明，在用土壤淋洗后，所有材料（包括石灰、生物炭和炭黑）的添加都对微生物修复表现出积极的影响。此外，石灰是最有效的材料，表明低土壤 pH 值和高酸溶性金属浓度可能会抑制土壤酶的活性。土壤 pH 值和养分是联合修复过程中微生物修复的主要考虑因素。这些发现表明，土壤淋洗和原位固定化的联合修复是一种有效修复受多种重金属污染土壤的方法。
