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Bioleaching of dewatered electroplating sludge for the extraction of base metals using an adapted microbial consortium: Process optimization and kinetics
Hydrometallurgy ( IF 4.7 ) Pub Date : 2020-01-01 , DOI: 10.1016/j.hydromet.2019.105227
Lijuan Zhang , Wenbo Zhou , Yongdi Liu , Honghua Jia , Jun Zhou , Ping Wei , Hongbo Zhou

Abstract The main objective of this study was to optimize bioleaching process parameters for high co-extraction of base metals (Cu, Ni, Zn, and Cr) from hazardous electroplating sludge using an adapted microbial consortium and to explore the relevant bioleaching mechanisms. Microbial cultivation and sludge bioleaching were separated. The effect of the relevant process parameters (i.e., bulk pH, pulp density, and Fe2+ concentration) on the extraction of four selected metals through bioleaching by an adapted microbial consortium was investigated in a 1 L stirred tank reactor. Results indicated that maximum metal solubilization (>95.6% for each of Cu, Zn, and Ni, and 90.3% of Cr) was achieved at a bulk pH of 2.0, Fe2+ of 9.0 g/L, and pulp density of 15% (w/v). Bioleaching kinetics of the selected metals was described by a modified shrinking core model. This indicated that the interfacial transfer and diffusion across the solid film layer was the rate controlling step and controlled the dissolution kinetics. Data from bioleaching and chemical leaching systems showed that bioleaching had some advantages over simple chemical leaching. The mechanisms of improved Cu, Ni, Zn, and Cr extraction by bioleaching were demonstrated. Bioleaching improved metal release, especially from the residual fraction, as indicated by Community Bureau of Reference (BCR) three-stage sequential extraction analysis. Most of the Cu, Ni, and Zn extraction was attributed to H+ attack, as these metals were primarily distributed in the water/acid soluble and exchangeable fractions, along with Fe and Mn oxyhydroxides (>72.3%). For the extraction of Cr, besides H+, microorganisms and Fe3+ were also responsible. They improved Cr extraction, especially from the residual fraction. These findings indicate that bioleaching with an adapted microbial consortium appears promising for recycling and reutilizing valuable heavy metals from hazardous electroplating waste.

中文翻译:

使用适应性微生物群落对脱水电镀污泥进行生物浸出以提取贱金属:工艺优化和动力学

摘要 本研究的主要目的是优化生物浸出工艺参数,以使用适应的微生物群落从危险电镀污泥中高共提取贱金属(Cu、Ni、Zn 和 Cr),并探索相关的生物浸出机制。微生物培养和污泥生物浸出分离。在 1 L 搅拌釜反应器中研究了相关工艺参数(即体积 pH 值、纸浆密度和 Fe2+ 浓度)对通过适应性微生物群落生物浸出提取四种选定金属的影响。结果表明,在体积 pH 为 2.0、Fe2+ 为 9.0 g/L 和纸浆密度为 15% (w /v)。所选金属的生物浸出动力学由改进的收缩核心模型描述。这表明跨固体膜层的界面转移和扩散是速率控制步骤并控制溶解动力学。来自生物浸出和化学浸出系统的数据表明,生物浸出比简单的化学浸出具有一些优势。证明了通过生物浸出改善 Cu、Ni、Zn 和 Cr 提取的机制。正如社区参考局 (BCR) 三阶段顺序提取分析所表明的那样,生物浸出改善了金属释放,尤其是从残余部分中释放。大多数 Cu、Ni 和 Zn 萃取归因于 H+ 侵蚀,因为这些金属主要分布在水/酸可溶性和可交换部分,以及 Fe 和 Mn 羟基氧化物 (>72.3%)。对于 Cr 的提取,除 H+ 外,微生物和 Fe3+ 也有责任。他们改进了 Cr 的提取,特别是从残余部分提取。这些发现表明,采用适应性微生物群落进行生物浸出似乎有望回收和再利用有害电镀废物中的有价值的重金属。
更新日期:2020-01-01
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