Zhao Liang, Fang Di, Shan Hong-xian, Jia Yong-gang
Key Laboratory of Marine Environment & Ecology, Ministry of Education, Ocean University of China, Qingdao 266100, China.
Huan Jing Ke Xue. 2009 Aug 15;30(8):2347-52.
The effect of total solids concentration on heavy metals bioleaching from contaminated sediment was investigated in shake flasks. The results demonstrated that an increase in total solids concentration reduced the rates of sediment pH reduction, ORP increase and metal removal. During this bioleaching process, the removal of Zn, Cu, and Cr rapidly enhanced and then gradually approached the maximum removal efficiency when sediment pH decreased from 5.0 to 2.0 and the ORP increased from 200 mV to 520 mV. After 12 days of bioleaching, about 60%-85% of Zn, 65%-100% of Cu, and 17%-35% of Cr could be removed from various sediments of 3%-13% solids content, respectively. It was found that the variation of sediment pH in this bioleaching process could be estimated by a modified Boltzmann model. The analysis of speciation distribution of metals indicated that the unremoved Cu, Zn, and Cr in the bioleached sediment mainly existed in residual fraction, and that the percentpages of Cu, Zn, and Cr bound to this fraction were 76.2%, 81.2%, and 82.7%, respectively. From economical consideration, the recommended total solids concentration for the bioleaching of metals from the sediment is 10%.
在摇瓶中研究了总固体浓度对污染沉积物中重金属生物浸出的影响。结果表明，总固体浓度的增加降低了沉积物pH值降低、氧化还原电位（ORP）升高和金属去除的速率。在该生物浸出过程中，当沉积物pH值从5.0降至2.0且ORP从200 mV升至520 mV时，锌、铜和铬的去除迅速增强，然后逐渐接近最大去除效率。生物浸出12天后，分别可从固体含量为3%-13%的各种沉积物中去除约60%-85%的锌、65%-100%的铜和17%-35%的铬。研究发现，该生物浸出过程中沉积物pH值的变化可用修正的玻尔兹曼模型估算。金属形态分布分析表明，生物浸出沉积物中未去除的铜、锌和铬主要以残渣态存在，与该形态结合的铜、锌和铬的百分比分别为76.2%、81.2%和82.7%。从经济角度考虑，沉积物中金属生物浸出的推荐总固体浓度为10%。
