College of Chemistry and Chemical Engineering, Tianjin Key Laboratory of Drug Targeting and Bioimaging, Tianjin Key Laboratory of Organic Solar Cells and Photochemical Conversion, Tianjin University of Technology, Tianjin, China.
College of Management Science and Engineering, Capital University of Economics and Business, Beijing, China.
PLoS One. 2020 Jan 29;15(1):e0226557. doi: 10.1371/journal.pone.0226557. eCollection 2020.
In this study, the Pb2+ biosorption potential of live and dead biosorbents of the hydrocarbon-degrading strain Rhodococcus sp. HX-2 was analyzed. Optimal biosorption conditions were determined via single factor optimization, which were as follows: temperature, 25°C; pH, 5.0, and biosorbent dose, 0.75 g L-1. A response surface software (Design Expert 10.0) was used to analyze optimal biosorption conditions. The biosorption data for live and dead biosorbents were suitable for the Freundlich model at a Pb2+ concentration of 200 mg L-1. At this same concentration, the maximum biosorption capacity was 88.74 mg g-1 (0.428 mmol g-1) for live biosorbents and 125.5 mg g-1 (0.606 mmol g-1) for dead biosorbents. Moreover, in comparison with the pseudo-first-order model, the pseudo-second-order model seemed better to depict the biosorption process. Dead biosorbents seemed to have lower binding strength than live biosorbents, showing a higher desorption capacity at pH 1.0. The order of influence of competitive metal ions on Pb2+ adsorption was Cu2+ > Cd2+ > Ni+. Fourier-transform infrared spectroscopy analyses revealed that several functional groups were involved in the biosorption process of dead biosorbents. Scanning electron microscopy showed that Pb2+ attached to the surface of dead biosorbents more readily than on the surface of live biosorbents, whereas transmission electron microscopy confirmed the transfer of biosorbed Pb2+ into the cells in the case of both live and dead biosorbents. It can thus be concluded that dead biosorbents are better than live biosorbents for Pb2+ biosorption, and they can accordingly be used for wastewater treatment.
在这项研究中，分析了烃降解菌株 Rhodococcus sp. HX-2 的活细胞和死细胞生物吸附剂对 Pb2+ 的吸附潜力。通过单因素优化确定了最佳吸附条件，分别为：温度 25°C；pH 值 5.0；生物吸附剂用量 0.75 g/L。使用响应面软件（Design Expert 10.0）分析了最佳吸附条件。在 Pb2+浓度为 200 mg/L 时，活细胞和死细胞生物吸附剂的吸附数据均适合 Freundlich 模型。在相同浓度下，活细胞生物吸附剂的最大吸附容量为 88.74 mg/g（0.428 mmol/g），而死细胞生物吸附剂的最大吸附容量为 125.5 mg/g（0.606 mmol/g）。此外，与准一级动力学模型相比，准二级动力学模型似乎更能描述吸附过程。死细胞生物吸附剂的结合强度似乎低于活细胞生物吸附剂，在 pH 值为 1.0 时具有更高的解吸能力。竞争金属离子对 Pb2+吸附的影响顺序为 Cu2+＞Cd2+＞Ni+。傅里叶变换红外光谱分析表明，死细胞生物吸附剂的吸附过程涉及几个官能团。扫描电子显微镜显示，Pb2+更容易附着在死细胞生物吸附剂的表面上，而透射电子显微镜则证实了 Pb2+在活细胞和死细胞生物吸附剂中均被转移到细胞内。因此，可以得出结论，死细胞生物吸附剂比活细胞生物吸附剂更适合用于 Pb2+的吸附，并且可以用于废水处理。
