| Microbial fuel cell (MFC) is a device of using microbial metabolism of organicmatter to generate electricity, which developed on the basis of MicrobialElectrochemical and Fuel Cell. In this paper, traditional dual-chambered microbialfuel cell was employed as the research object. In the first place, air was bubbled intocathode as electron acceptor. Effect of a series of abiotic factors on power generationperformance was analyzed, and then optimized power generation performance of theMFC. In the next place, based on the air-cathode, the study of electricity generationperformance and influencing factors on the treatment of Cr(VI)-containingwastewater using MFC.When air was as the cathode electron acceptor, in order to obtain the optimalelectricity generation performance, the anode substrate, ion exchange membrane andcathodic electron acceptor had been changed, which influences on MFC electricitygeneration performance were analyzed. Results of this part are as follows:(1) Withsodium acetate as the anode substrate, the start-up stage spent （15days) less timethan glucose. But when glucose was as the substrate，the electricity generationperformance was improved, the largest open circuit voltage(OCV) reached618(552)mV and the maximum power density reached54.39(46.12) mW/m2;(2) The way ofanodic nutrient supply also could affect the electricity generation performance. Themaximum power density of continuous supply was12.33mW/m2higher thansequencing supply type;(3) Under the condition of catholyte remained neutral, theMFC with proton exchange membrane (PEM) was best and OCV could reach654mV,it was higher than cation exchange membrane (CEM)-632mV and anion exchangemembrane-619mV. Three exchange membranes obtained maximum power densitieswere77.01,66.72and57.18mW/m2, respectively, the PEM was also the maximum inthis aspect;(4) Carbon cloth, ordinary graphite plate and the spectrum pure graphite(SPG) plate were used in the cathode respectively. Comparing with them, the OCV of using SPG was618mV and the maximum power density was72.96mW/m2, whichwas the best among three of them;(5) The electricity generation performance of air,potassium dichromate and sodium persulfate as cathodic electron acceptor underacidic conditions were studied. Sodium persulfate as electron acceptor had the highestOCV and maximum power density（1412mV and674.16mW/m2）, but its electricitygeneration was unstable. When potassium dichromate was as electron acceptor, OCVreached1339mV and the maximum power density was568.43mW/m2. Althoughpotassium dichromate was relatively lower than sodium persulfate, its electricitygeneration was stable and efficient. So potassium dichromate could regard as idealelectron acceptor.All of pH, initial concentration of Cr(VI) and air-bubbling were important factorsfor hexavalent chromium removal efficiency and electricity generation performanceon the treatment of Cr(VI)-containing wastewater by using the technology of MFCwith an air-cathode. Conclusions of this part are as follows:(1) The removalefficiency of Cr(VI) and electricity generation performance were increased when pHvalue was decreasing, the best treatment effect of Cr(VI)was achieved when the pHdepressed to2,the removal rate of Cr(VI) with the concentration of50mg/L reached100%after50h treatment, at the same time the maximum power density of MFCcould attain568.42mW/m2;（2）Based on the best pH=2, the required time toremoval Cr(VI) increased with the lift of initial concentration of Cr(VI), however themaximum power density was enhanced. The maximum power density could get to705.33mW/m2when the initial concentration was100mg/L;(3) Compared withN2-bubbling and air-bubbling, H2O2may be generated when using air-bubbling andaccelerated the removal efficiency of Cr(VI), this phenomenon was more significantwhen the concentration of Cr(VI) was lower. In addition, the air-bubbling couldreduce the internal resistance and cathodic polarization, thus electricity generationperformance could improve. |
PDF Full Text Request