基于季铵化壳聚糖/石墨烯复合材料的污水电容去离子灭菌性能研究

This project try to improve the capacitive deionization technique with a macroporous quanternized chitosan-graft-graphene film to disinfect waste water. In this funding, the research focus on the relationship between the sidechain of chitosan after grafting it onto the graphene flakes and their antibacterial property. The advantage of this technique is that both ions and bacterial could be removed together from bio-contaminate water as the liquid flow through the electrodes with this antibacterial coating. In charging step, the microbes are absorbed onto the corresponding electrode and they are killed by the quanternized chitosan. While in discharging step, both the absorbed ions and the dead bacterial are released and pumped out of the device so that the active carbon electrodes and the antibacterial film are successfully regenerated. By alternating charging step and discharging step, the deionization disinfection of dirty water process is continuous. As bacterial attach onto the quanternized chitosan-graft-graphene film, the cationic chitosan could disrupt the anionic microbial envelope and kill them. At the same time, the ions could pass through the macroporous three dimensional graphene freely and are absorbed on the active carbon surface. Compared with directly dissolving chlorine or peroxides in water, the quanternizaed chitosan which are fixed on the graphene surface show an excellent anti-bacterial property and non-leachable to water. So there is no need to remove the disinfectant again. This capacitive deionization disinfection technique shows an ultrafast, non-contaminating and continuous process for waste water purification. Therefore, as an emerging technique, it certainly offers a novel, eco-friendly way for water disinfection and deionization.

该项目立足于低能耗、可循环再生的电容去离子技术，旨在通过季铵化壳聚糖/石墨烯抗菌复合膜改进电容去离子装置。在离子吸附阶段，污水中的细菌由于带有电荷可以被相应电极吸附并在季铵化壳聚糖作用下死亡，脱盐/灭菌同步完成，实现污水净化；而后，在解吸附阶段，电极吸附的盐离子和死细菌被排出装置，实现抗菌复合膜/脱盐电极同步再生。注重研究季铵化壳聚糖分子结构变化对抗菌性能的影响以及季铵化壳聚糖接枝到石墨烯后的杀菌原理和效果。此外，研究控制三维石墨烯复合膜的孔道结构的方法，确保盐离子吸附/解吸附过程不受影响，同时其大比表面积又可以提高盐离子吸附量。与高氯酸盐、过氧化物等杀菌剂直接溶解在水中相比，季铵化壳聚糖通过共价键接枝于石墨烯膜上，既可以保持优异的广谱抗菌效果，又不会在水中形成二次污染。与其它水再生过程相比，此技术具有装置结构简单成本低、工作能耗低、环境友好等优点，在国内外受到广泛关注。该项研究可赋予电容去离子过程优异的杀菌能力，实现污水脱盐、脱菌同步完成，为推进电容去离子技术的工程应用提供理论和技术支撑。

电容去离子技术作为一种咸水淡化技术，具有装置结构简单、工作能耗低、电极可原位再生等优点，是反渗透、电渗析和多效蒸发等脱盐技术有力竞争者。但是在电容去离子脱盐过程中，咸水中的细菌在装置内部滋生造成电极污染，破坏出口水质。研究旨在通过季铵盐/碳纳米材料抗菌复合材料涂层，实现咸水脱盐与灭菌同步完成并能够在电极再生步骤实现抗菌涂层再生，提高装置稳定性。研究的主要内容包括：.（1）季铵化腰果酚/碳纳米复合材料制备。腰果酚分子中引入不同数量季铵氮，证明其结构与抗菌性能的关系。双季铵氮的腰果酚对大肠杆菌和金色葡萄球菌的MIC分别为8和4 μg·mL-1，抗菌性最好。季铵化腰果酚/碳纳米管复合物制备及其水相抗菌性能测试。复合物的对大肠杆菌和金黄色葡萄球菌MIC分别为0.33和0.02 μg·mL-1。.（2）电容去离子多孔碳电极制备。聚酰亚胺和三聚氰胺甲醛树脂为前驱体制备多孔碳。我们一共制备花状，实心球状和空心球状三种多孔碳电极，孔径为4 nm，接近理论最优值。NaCl脱除能力分别为13.9 mg/g,15.9 mg/g可稳定循环超过500次。.（3）联萘聚酰亚胺基碳分子筛气体分离膜的合成。以三氨基苯基苯和六氟二酐为单体，我们通过控制单体聚合速度成功制备了自支撑超支化聚酰亚胺薄膜，碳化后可以CO2/N2选择性可达34.7，同时CO2透气性为16564.4 barrer；合成酚羟基联萘链状聚酰胺酸，并通过乙酸酐亚胺化同步酯化酚羟基。该过程主链扭转与亚胺化一步完成，既提高膜内的高分子链间距又简化制备流程。酯基在碳化过程中热解可以形成连续气体分子扩散孔道，碳分子筛膜的CO2/N2选择性为32.6，CO2透气性为465.6 barrer。.通过抗菌涂层的合成和离子吸附电极的制备两方面来提高电容去离子装置稳定性和效率。在这个过程中，将多孔碳电极孔径控制方法应用到碳分子筛气体分离膜制备，获得了理想的气体分离膜。两者都有较强的工业应用前景。