美国宾夕法尼亚大学和中国清华大学的最新研究显示，细菌可将污浊的盐水变为饮用水并发电。

该研究昭示着微生物燃料电池的发展新方向。过去，微生物燃料电池通常被用于发电或以氢气或甲烷的形式储存电力。

据探索频道报道，宾夕法尼亚大学科学家布鲁斯·洛根（Bruce Logan）表示，微生物燃料电池可将有机废物转变为能量来源。洛根和其他作者在《环境科学与技术》杂志（Environmental Science and Technology）上发表了一篇相关论文。洛根说：“在这个最新发现中，我们认为，通过改变微生物的发电情况，我们可以将盐水进行淡化处理。”

研究人员首先从池塘或其他天然水域采集样品。在样品的数百万微生物中，一些细菌（科学家尚未确定其种类）会自动地在其细胞内产生电子和质子，并将它们转运到体外。其他细菌会吸收这些电子和质子，将其作为创造氢、甲烷和其他化学物质等能量物质的“燃料”。

研究人员发现，使用两片特制的塑料薄膜就可以利用这些微生物所产生的能量。这种薄膜可以分离微生物产生的电子、离子或气体，让其分别流向阴极或阳极。阴极、阳极和薄膜组装在一个如同小纸巾盒一样的透明塑料盒中。在薄膜之间加入一杯池塘里的水，细菌就开始工作，最终可以产生纯度达90%的水。

水的纯度可以根据科学或商业需要进行调整，甚至可以达到饮用水标准。微生物燃料电池可以去除水中的大部分盐分，由于该过程能够减少电力消耗，因此还可以降低水质淡化成本。

同样也在研究微生物燃料电池的俄勒冈州立大学刘洪（音译）表示：“无论处理后水的盐度如何，这将是人类第一次把微生物燃料电池用于盐水淡化。”

刘洪认为：“使用此方法，基本上不需要输入能量；如果人为地将有机材料添加到电池中，甚至还可以产生能量。”

目前，无论是淡化盐水、产生电力还是生产氢、甲烷或其他气体，微生物燃料电池都仅限于实验室。这种情况将在下个月有所改变，洛根和其同事在一座酒厂附近安装了一个大型微生物燃料电池，计划将其产生的废水变成氢气。

洛根表示：“目前这只是一个示范项目。但最终酒厂将可以利用微生物燃料电池产生的电力驱动轿车、铲车和其他车辆。”

Environ. Sci. Technol., Article ASAP DOI: 10.1021/es901950j

A New Method for Water Desalination Using Microbial Desalination Cells

Xiaoxin Cao, Xia Huang*, Peng Liang, Kang Xiao, Yingjun Zhou, Xiaoyuan Zhang and Bruce E. Logan

State Key Joint Laboratory of Environment Simulation and Pollution Control, Department of Environmental Science and Engineering, Tsinghua University, Beijing, 100084, P.R. China, and Engineering Environmental Institute, Penn State University, University Park, Pennsylvania

Current water desalination techniques are energy intensive and some use membranes operated at high pressures. It is shown here that water desalination can be accomplished without electrical energy input or high water pressure by using a source of organic matter as the fuel to desalinate water. A microbial fuel cell was modified by placing two membranes between the anode and cathode, creating a middle chamber for water desalination between the membranes. An anion exchange membrane was placed adjacent to the anode, and a cation exchange membrane was positioned next to the cathode. When current was produced by bacteria on the anode, ionic species in the middle chamber were transferred into the two electrode chambers, desalinating the water in the middle chamber. Proof-of-concept experiments for this approach, using what we call a microbial desalination cell (MDC), was demonstrated using water at different initial salt concentrations (5, 20, and 35 g/L) with acetate used as the substrate for the bacteria. The MDC produced a maximum of 2 W/m2 (31 W/m3) while at the same time removing about 90% of the salt in a single desalination cycle. As the salt was removed from the middle chamber the ohmic resistance of the MDC (measured using electrochemical impedance spectroscopy) increased from 25 Ω to 970 Ω at the end of the cycle. This increased resistance was reflected by a continuous decrease in the voltage produced over the cycle. These results demonstrate for the first time the possibility for a new method for water desalination and power production that uses only a source of biodegradable organic matter and bacteria.