摘要
本研究以竹溶解浆为原料,通过简单的溶解再生技术制备高性能的纤维素膜,并通过调节成膜的厚度得到离子电导率为0.099 mS/cm的膜材料。结果表明,较低厚度的纤维素膜可以产生较高的开路电压、短路电流和功率输出密度:在500倍盐浓度差下,32 μm纤维素膜具有-119 mV的开路电压、132.4 μA短路电流和16.33 mW/
随着世界经济的快速发展,全球的化石资源被急剧消耗。化石资源的不可再生性终会诱发世界资源的短缺问题,并伴随着一系列的环境污染。因此,开发具有可持续的、清洁的新型能源对世界各国长久、稳定的发展与进步具有深远意
反向电渗析体系(reverse electrodialysis,RED)是收集海洋盐差能的主要方式。典型的RED器件由阳离子交换膜和阴离子交换膜交替组
纤维素是自然界中来源广泛、储量丰富的可再生资
称取30 g AMIMCI放入250 mL三口烧瓶中,油浴加热至90℃后缓慢加入1.8 g竹溶解浆,继续搅拌90 min。反应结束后静置10 min除气泡。采用刮膜器制备不同厚度的纤维素膜,然后浸泡在去离子水中除去离子液体。最后室温干燥纤维素膜,纤维素膜的厚度分别为32、56、108 μm。
采用热重分析仪(STA449C,NETZSCH公司)在N2环境中测试纤维素膜的热稳定性能。N2的流速20 mL/min,温度30~800℃,升温速率10℃/min。通过N2吸脱附等温仪(多站全自动比表面积与孔隙度分析仪,ASAP2460,Micromeritics公司)测量纤维素膜的孔径。利用傅里叶变换红外光谱仪(FT-IR,AVATAR 380,美国Thermo-Nicolet公司)测量纤维素膜的功能基团,扫描范围600~4000 c
首先考察纤维素膜在不同盐浓度条件下的离子传输行为,纤维素膜厚度对离子电导率的影响见
图2 纤维素膜厚度对离子电导率的影响
Fig. 2 Effect of cellulose membranes thickness on the ionic conductivity
进一步采用纤维素膜构建盐差发电器件(见
图3 纤维素膜的I-V曲线
Fig. 3 I-V curves of cellulose membranes
将包含纤维素膜的H型电解池连接电阻箱,利用电化学工作站分析纤维素膜器件的输出功率密度和电流密度,结果如
图4 纤维素膜器件的输出功率密度
Fig. 4 Output power density of cellulose membranes
图5 纤维素膜器件的电流密度
Fig. 5 Current density of cellulose membranes
纤维素分子中含有大量的功能基团和化学键,如羟基(—OH)和醚键(C—O—C)。纤维素膜的FT-IR如
图6 纤维素膜化学结构及表面电位
Fig. 6 Chemical structure and surface potential of cellulose membranes
基于N2吸附-脱附理论,探究纤维素膜的孔径大小及其分布,结果如
图7 纤维素膜厚度对其孔径的影响
Fig. 7 Effect of cellulose membranes thicknes on its pore size
本研究采用氯化1-烯丙基-3-甲基咪唑(AMIMCI)溶解竹纤维素,通过溶解再生过程制备了不同厚度的纤维素膜。
3.1 纤维素膜表面暴露大量的羟基功能团可以赋予纤维素膜较高的Zeta电位。此外,纤维素膜的孔径可以控制在纳米级别。这种物理、化学特性使纤维膜具有较好的离子选择性,其离子电导率可达0.099 mS/cm,可以组装性能优异的盐差发电器件。
3.2 较低厚度的纤维素膜可能具有较短的离子传输路径,离子传输性能较好,从而使其具有优异的电学性能,在500倍盐浓度差条件下,厚度32 μm纤维素膜的最大输出功率密度为16.33 mW/
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