Characterization of cadmium biosorption by Exiguobacterium sp. isolated from farmland soil near Cu-Pb-Zn mine
Characterization of cadmium biosorption by Exiguobacterium sp. isolated from farmland soil near Cu-Pb-Zn mine
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DOI：
10.1007/s11356-016-6335-8
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发表时间：
2016-03
影响因子：
5.8
通讯作者：
J. Park;H. Chon
中科院分区：
文献类型：
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作者：
J. Park;H. Chon
细菌具有将重金属结合在细胞壁上的能力。生物吸附是一种被动的、不依赖能量的重金属吸附机制。重金属生物吸附的效率可以根据几个因素而变化，例如细菌的生长阶段，溶液pH值和竞争性重金属的存在。在本研究中，将产芽孢杆菌属（Agrobacteriumsp.）从矿区附近农田土壤中分离得到的3种重金属离子，研究了它们对溶液中Cd的最佳吸附条件。随着细菌生长的进行，镉的生物吸附增加，这是由于在细菌生长过程中的细胞壁的结构和组成的变化。生物吸附过程迅速，在30 min内完成。在pH 7时，Cd的吸附量最大，主要是由于pH值升高导致的氢离子解离和负电荷的增加。在Cd、Pb和Zn的混合溶液中，吸附量的大小顺序为Pb>Cd>Zn，而在单一金属溶液中，吸附量的大小顺序为Cd≥Pb>Zn。根据Langmuir吸附等温线模型计算得到，该菌对Cd的最大吸附量为15.6 mg/g生物量。在不同的环境条件下的不同吸附效率表明，为了控制金属的流动性，生物吸附的条件，应优化之前应用细菌。结果表明，所分离的细菌可用于金属污染废水中金属的去除。
Bacteria have the ability to bind heavy metals on their cell wall. Biosorption is a passive and energy-independent mechanism to adsorb heavy metals. The efficiency of heavy metal biosorption can vary depending on several factors such as the growth phase of bacteria, solution pH, and existence of competitive heavy metals. In this study,Exiguobacteriumsp. isolated from farmland soil near a mine site were used, and optimal conditions for Cd biosorption in solution were investigated. As bacterial growth progressed, Cd biosorption increased, which is attributed to changes in the structure and composition of the cell wall during bacterial growth. The biosorption process was rapid and was completed within 30 min. Cadmium biosorption was highest at pH 7 due to the dissociation of hydrogen ions and the increase of negative charges with increasing pH. In the mixed metal solution of Cd, Pb, and Zn, the amount of biosorption was in the order of Pb>Cd>Zn while in a single metal solution, the order was Cd≥Pb>Zn. The maximum adsorption capacity for Cd by the isolated bacteria was 15.6 mg/g biomass, which was calculated from the Langmuir isotherm model. Different adsorption efficiencies under various environmental conditions indicate that, to control metal mobility, the conditions for biosorption should be optimized before applying bacteria. The results showed that the isolated bacteria can be used to immobilize metals in metal-contaminated wastewater.