Roh Y, Vali H, Phelps T J, Moon J W
Faculty of Earth Systems and Environmental Sciences, Chonnam National University, Gwangju, 500-757, Korea.
J Nanosci Nanotechnol. 2006 Nov;6(11):3517-20.
We have developed a novel microbial process that exploits the ability of Fe(III)-reducing microorganisms to produce copious amounts of extracellular magentites and metal-substituted magnetite nanoparticles. The Fe(III)-reducing bacteria (Theroanaerobacter ethanolicus and Shewanella sp.) have the ability to reduce Fe(III) and various metals in aqueous media and form various sized magnetite and metal-substituted magnetite nano-crystals. The Fe(III)-reducing bacteria formed metalsubstituted magnetites using iron oxide plus metals (e.g., Co, Cr, Mn, Ni) under conditions of relatively low temperature (<70 degrees C), ambient pressure, and pH values near neutral to slightly basic (pH = 6.5 to 9). Precise biological control over activation and regulation of the biosolid-state processes can produce magnetite particles of well-defined size (typically tens of nanometers) and crystallographic morphology, containing selected dopant metals into the magnetite (Fe(3-y)XyO4) structure (where X = Co, Cr, Mn, Ni). Magnetite yields of up to 20 g/L per day have been observed in 20-L vessels. Water-based ferrofluids were formed with the nanometer sized, magnetite, and metal-substituted biomagnetite particles.
我们开发了一种新型微生物工艺，该工艺利用铁（III）还原微生物的能力来大量生产细胞外磁铁矿和金属取代的磁铁矿纳米颗粒。铁（III）还原细菌（乙醇嗜热厌氧菌和希瓦氏菌属）能够在水性介质中还原铁（III）和各种金属，并形成各种尺寸的磁铁矿和金属取代的磁铁矿纳米晶体。铁（III）还原细菌在相对低温（<70摄氏度）、常压以及pH值接近中性至微碱性（pH = 6.5至9）的条件下，使用氧化铁加金属（如钴、铬、锰、镍）形成金属取代的磁铁矿。对生物固态过程的激活和调节进行精确的生物控制，可以产生尺寸明确（通常为几十纳米）且晶体形态良好的磁铁矿颗粒，其中选定的掺杂金属进入磁铁矿（Fe(3-y)XyO4）结构（其中X = 钴、铬、锰、镍）。在20升容器中观察到磁铁矿产量高达每天20克/升。纳米尺寸的磁铁矿和金属取代的生物磁铁矿颗粒形成了水基铁磁流体。
