纳米Fe₃O₄固定化腐败希瓦氏菌处理水体铅污染的研究

Study on the Treatment of Lead Pollution in Water by Nano-Fe₃O₄ Immobilized Shewanella putrefaciens

摘要: 目的：探索纳米材料固定化腐败希瓦氏菌对Pb²⁺的去除作用，并对固定化小球去除作用的机理进行了初步探讨。方法：腐败希瓦氏菌的死活细胞以海藻酸钠(SA)和纳米Fe₃O₄作为固定化材料，制备固定化小球进行Pb²⁺去除实验，通过原子分光光度计检测去除效率的变化并利用扫描电子显微镜(SEM)观察固定化小球吸附前后的表面特征的变化。结果：不管固定材料选择海藻酸钠(SA)还是海藻酸钠 + 纳米Fe₃O₄ (SA-Fe)，腐败希瓦氏菌死细胞的去除效率均高于活细胞，SA + Fe + 腐败希瓦氏菌死细胞(SA-Fe-Xs)对Pb²⁺的去除效率高达92.11%；扫描电子显微镜显示去除实验后，固定化小球表面整体变得平整，结构致密，说明Pb²⁺可能是通过吸附作用附着在固定化小球的表面。结论：海藻酸钠和纳米Fe₃O₄固定化腐败希瓦氏菌在去除Pb²⁺方面有较强的优势。

Abstract: Aim: To explore the removal of heavy metal Pb²⁺ by immobilized Shewanella putrefaciens in nanomaterials, and to explore the mechanism of immobilized ball. Methods: The dead cells of Shewanella putrefaciens were prepared with sodium alginate (SA) and nano-Fe₃O₄ as immobiliza-tion materials and the immobilized beads were prepared for removal experiments. The removal efficiency was measured by atomic spectrophotometer. The changes in surface structure before and after adsorption of immobilized beads were observed with scanned electron microscopy (SEM). Results: Regardless of whether the fixed material selected sodium alginate (SA) or sodium alginate + nano-Fe₃O₄ (SA + Fe), the removal efficiency of dead cells was higher than that of living cells. The removal efficiency of Pb²⁺ by the beads of sodium alginate + nano-Fe₃O₄+ Shewanella putrefaciens (SA + Fe + Xs) was as high as 92.11%. Scanning electron microscopy showed that the surface of the immobilized spheres became flat and dense after the removal experiment, which may further indicate that Pb²⁺ may adhere to the surface of the immobilized beads by adsorption. Conclusion: The dead cells of Shewanella putrefaciens have a stronger advantage in removing heavy metal Pb²⁺; nano-Fe₃O₄ has great potential as a microbial immobilization material.