侧链型磺化聚芳醚阳离子交换膜在微生物燃料电池中的应用

Cation Exchange Membranes based on Side-chain Type Sulfonated Poly( aryl ether) s for Microbial Fuel Cell Applications

采用芳香亲核取代反应及溶液铸膜法,制备了一系列具有不同离子交换容量(IEC)的侧链型磺化聚芳醚砜(s SPFAE)阳离子交换膜,并作为分离膜应用于微生物燃料电池(MFC).研究了s SPFAE膜在双室MFC中产电性能并与商用阳离子交换膜进行了对比.s SPFAE膜的IEC为0.97~1.56 mmol/g,厚度约为80μm,在30℃时吸水率为20.9%~41.7%,电导率达到27.3~60.5 m S/cm,高于商用膜(22 m S/cm,420μm).对采用s SPFAE膜的MFC,根据峰功率密度法及极化曲线斜率法得到的MFC内阻约为29~64Ω,随着IEC的升高而降低,库伦效率达到47.7%~55%,其中s SPFAE-1.56膜的最大功率密度达到657.3 m W/m^2,且s SPFAE膜均表现出优于商用膜的产电性能.利用模拟等效电路对整个MFC系统进行EIS分析,结果表明阳极扩散内阻占这类MFC系统总内阻的87%~90%.结合循环伏安曲线、电化学阻抗谱测试及电极电势分析结果,表明分离膜对两极室间物质传递及阳极扩散阻抗有较大的影响.

A series of cation exchange membranes （CEMs） with different ion exchange capacitiy （IEC） values based on side-chain type partially fluorinated sulfonated poly （aryl ether）s （sSPFAEs） are prepared through aromatic nueleophilic substitution and solution casting, and subsequently used as the separator in microbial fuel cell （MFC）. Their power production performances in double chamber MFCs are investigated and compared with commercial CEM. The obtained sSPFAE membranes have IEC of 0.97 - 1.56 mmol/g with thickness around 80 μm,show water uptakes of about 20.9% -41.7% ,and proton conductivities of 27.3 - 60.5 mS/cm,which are higher than those for commercial CEM with thickness of 420 μm （22 mS/cm）. For the MFCs with sSPFAE membranes, the intermal resistances are in the range of 29 - 64 Ω according to the peak power density and the slope method from the polarization curves, and increase with the IEC; their columbic efficiencies are about 47.7% - 55%. The membrane of sSPFAE-1.56 exhibits the maximum power output of 657.3 mW/cm2 and all the sSPFAE membranes outperform commercial CEM. According to the EIS analysis results for the whole MFC system by equivalent circuit simulation,the anodic diffusion resistances hold 87% -90% of the total resistances. Combining the CV analysis and EIS analysis with the electrode potential test results,the separating membranes have considerable influence upon the mass tranfer across the chambers as well as the anodic diffusion resistance.