基于空气阴极微生物燃料电池处理含铬（Ⅵ）废水的研究

发布时间：2018-08-18 17:43

【摘要】：微生物燃料电池(MFC)是一种利用微生物代谢有机质产生电能的装置，在微生物电化学和燃料电池的基础上发展起来。本文采用传统的双室微生物燃料电池为研究对象，，以空气作为阴极电子受体，分析了一系列非生物因素对其产电性能的影响，优化了MFC产电性能；接着在空气阴极微生物燃料电池的基础上，研究MFC处理含铬废水时的产电性能和影响因素。 为了优化MFC的产电性能，以空气作为阴极电子受体，通过改变阳极底物、离子交换膜和阴极电子受体等条件，分析其对MFC产电性能的影响。研究结果显示：（1）以乙酸钠为阳极底物时，启动过程中所用时间（15天）较少，而以葡萄糖为底物时产电性能较乙酸钠作底物时有所提高，最大开路电压OCV达到618（552）mV，最大功率密度为54.39（46.12）mW/m2；（2）阳极营养液的供给方式也对产电性能有所影响，连续式供给时的MFC获取的最大功率密度要比序批式供给高出12.33mW/m2；（3）阴极液中性条件下，采用质子交换膜（PEM）时MFC的产电性能最佳，OCV达654mV，与阳离子交换膜（CEM）时的632mV和阴离子交换膜（AEM）时的619mV相比略有高，可获得最大功率密度分别为77.01、66.72和57.18mW/m2，仍是PEM时最高；（4）阴极分别采用碳布、普通石墨板、光谱纯（SPG）石墨板，对比发现采用SPG石墨板时可获取的OCV为618mV，最大功率密度为72.96mW/m2，都为三者中的最高；（5）对比空气、重铬酸钾和过硫酸钠在酸性条件下作为阴极电子受体时的产电性能，过硫酸钠作阴极电子受体时，虽然OCV和最大功率密度都为三者最高（分别为1412mV和674.16mW/m2），但是其产电不稳定，重铬酸钾作阴极电子受体时，OCV达到1339mV，最大功率密度为568.43mW/m2，较过硫酸钠来说都有所降低，但是产电稳定高效，是比较理想的电子受体。 基于空气阴极的MFC处理含铬(Ⅵ)废水时，pH、六价铬初始浓度和曝气都是六价铬去除效率和产电性能的重要影响因素。研究结论如下：（1）六价铬的去除效率和产电性能都随着pH值的降低而升高，在pH=2时六价铬达到最佳的处理效果，浓度为50mg/L的六价铬经过50h的处理后，去除率达到100%，同时能够获得最大的功率密度568.42mW/m2；（2）基于最佳的pH=2，随着六价铬初始浓度的增加，六价铬去除所需要的时间随之增加，但是所获得的最大功率密度却有所增加。当初始浓度达到100mg/L时，可获取的最大功率密度可达到705.33mW/m2；（3）通过曝氮气和曝空气的比较，推断曝空气时可能生成了中间产物H2O2，加快了六价铬的去除，且在六价铬浓度较低时表现明显。另外，曝空气能降低电池内阻和减小阴极极化，从而增大产电性能。
[Abstract]:Microbial fuel cell (MFC) is a kind of device which uses microbial metabolized organic matter to produce electric energy. It is developed on the basis of microbial electrochemistry and fuel cell. In this paper, the effects of a series of abiotic factors on the electrical properties of conventional two-chamber microbial fuel cells were analyzed, and the electrical properties of MFC were optimized by using air as cathode electron receptor. Then, on the basis of air cathode microbial fuel cell, the electrical properties and influencing factors of MFC treatment of chromium-containing wastewater were studied. In order to optimize the electrical properties of MFC, the influence of air as cathode electron receptor on the electrical properties of MFC was analyzed by changing the anode substrate, ion exchange membrane and cathode electron receptor. The results showed that: (1) when sodium acetate was used as anode substrate, the starting time (15 days) was less, but the electrical performance of glucose substrate was improved than that of sodium acetate substrate. The maximum open circuit voltage (OCV) reached 618 (552) MV and the maximum power density was 54.39 (46.12) MW / m2. (2) the supply mode of anodic nutrient solution also affected the electrical performance. The maximum power density obtained by MFC with continuous supply was 12.33 MW / m2 higher than that of sequential batch supply. (3) under neutral cathodic solution, MFC with proton exchange membrane (PEM) had the best electrical performance of 654mV, which was slightly higher than that of 632mV with cationic exchange membrane (CEM) and (AEM) with anion exchange membrane. The maximum power density is 77.01mW / m2 and 57.18mW / m2 respectively, which is still the highest at PEM. (4) the cathode adopts carbon cloth, ordinary graphite plate and spectral pure (SPG) graphite plate, respectively. It was found that the OCV obtained with SPG graphite plate was 618mV and the maximum power density was 72.96mW / m2, which was the highest of the three. (5) the electrical properties of air, potassium dichromate and sodium persulfate as cathode electron receptors under acidic conditions were compared. When sodium persulfate acts as cathode electron acceptor, although OCV and maximum power density are the highest (1412mV and 674.16mW/m2, respectively), the generation of electricity is unstable. When potassium dichromate acts as cathode electron acceptor, the OCV is 1339mV, and the maximum power density is 568.43mW / m2, which is lower than sodium persulfate, but the generation of electricity is stable and efficient, so it is an ideal electron acceptor. The pH of chromium (鈪

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