Centre for Mechanical Engineering, Materials and Processes (CEMMPRE), ARISE, Department of Life Sciences, Universidade de Coimbra, 3000-456, Coimbra, Portugal.
Chemical Engineering and Renewable Resources for Sustainability (CERES), Department of Civil Engineering, Universidade de Coimbra, R. Luís Reis Santos, 3030-788, Coimbra, Portugal.
Sci Rep. 2024 Oct 26;14(1):25583. doi: 10.1038/s41598-024-75840-0.
Mine waste can be transformed into technosol as an ecological strategy. Despite its importance to soil functions, biological activity is often overlooked. Biopolymers can serve as innovative tools for bioremediation, facilitating chemical reactions and creating networks to encapsulate contaminants. This work aims to assess the use of bioleached and stabilised residues from a tungsten mine for technosol production. The first objective was to evaluate mine tailings for their bioleaching potential by biostimulation or bioaugmentation with strain Diaphorobacter polyhydroxybutyrativorans B2A2W2. The second was to evaluate the effect of Portland cement or biopolymers such as Carboxymethyl Cellulose (CMC) or Xanthan Gum (XG) on the stabilisation of bioleached residues. The impact of biopolymers on residues' characteristics, such as metal leaching, number of cultivable microorganisms, compression strength and ecotoxicity was evaluated using flow systems. Over time, bioleached metallic elements decreased, except for iron (Fe). Biostimulated and stabilised residues exhibited similar trends; both CMC and cement showed low leaching rates and viable microorganisms in the same order (10 CFU × ml). However, bioaugmented residue stabilised with XG showed 10 CFU × ml viable microorganisms and increased 2.2-fold Fe leaching than BA_Control. CMC addition to bioaugmented residue reduced 5.9-fold Fe leaching and increased 100-fold viable microorganisms. By utilising both biological and engineering approaches to characterise the technosol, this study contributes to advancing knowledge of technosol production. The residues biostimulated and stabilised with CMC produced a material useful for bio-applications, with low toxicity and metal leaching, useful for bio-applications. XG was the best stabiliser for geotechnical engineering applications, with improved compression strength. In conclusion, the study demonstrates the usefulness of biopolymer treatment for residues and emphasises the importance of selecting the appropriate biopolymer for the intended function of technosols.
矿山废物可以转化为技术土壤，作为一种生态策略。尽管它对土壤功能很重要，但生物活性往往被忽视。生物聚合物可以作为生物修复的创新工具，促进化学反应并形成网络来包裹污染物。本工作旨在评估利用钨矿的生物浸出和稳定化残渣来生产技术土壤。第一个目标是通过生物刺激或用菌株 Diaphorobacter polyhydroxybutyrativorans B2A2W2 进行生物强化来评估尾矿的生物浸出潜力。第二个目标是评估波特兰水泥或生物聚合物（如羧甲基纤维素（CMC）或黄原胶（XG））对生物浸出残渣稳定化的影响。使用流动系统评估生物聚合物对残渣特性（如金属浸出、可培养微生物数量、压缩强度和生态毒性）的影响。随着时间的推移，生物浸出的金属元素除铁（Fe）外均减少。生物刺激和稳定化的残渣表现出相似的趋势；CMC 和水泥均表现出较低的浸出率和相同数量的存活微生物（10 CFU×ml）。然而，用 XG 稳定化的生物强化残渣表现出 10 CFU×ml 的存活微生物和比 BA_Control 增加 2.2 倍的 Fe 浸出。CMC 的添加减少了生物强化残渣中 5.9 倍的 Fe 浸出，并将存活微生物增加了 100 倍。通过利用生物学和工程学方法来描述技术土壤，本研究有助于推进技术土壤生产的知识。用 CMC 生物刺激和稳定化的残渣生产出了一种可用于生物应用的材料，具有低毒性和低金属浸出率，可用于生物应用。XG 是用于岩土工程应用的最佳稳定剂，可提高压缩强度。总之，该研究证明了生物聚合物处理残渣的有用性，并强调了为技术土壤的预期功能选择合适的生物聚合物的重要性。
