Department of Chemical and Environmental Engineering, Yale University, P.O. Box 208286, New Haven, Connecticut 06520-8286, United States.
ACS Appl Mater Interfaces. 2011 Aug;3(8):2869-77. doi: 10.1021/am200536p. Epub 2011 Jun 30.
We propose an innovative approach to impart nanomaterial-specific properties to the surface of thin-film composite membranes. Specifically, biocidal properties were obtained by covalently binding single-walled carbon nanotubes (SWNTs) to the membrane surface. The SWNTs were first modified by purification and ozonolysis to increase their sidewall functionalities, maximize cytotoxic properties, and achieve dispersion in aqueous solution. A tailored reaction protocol was developed to exploit the inherent moieties of hand-cast polyamide membrane surfaces and create covalent amide bonds with the functionalized SWNTs. The reaction is entirely aqueous-based and entails activation of the carboxylate groups of both the membrane and the nanomaterials to maximize reaction with ethylenediamine. The presence of SWNTs was verified after sonication of the membranes, confirming the strength of the bond between the SWNTs and the membrane surface. Characterization of the SWNT-functionalized surfaces demonstrated the attainment of membranes with novel properties that continued to exhibit high performance in water separation processes. The presence of surface-bound antimicrobial SWNTs was confirmed by experiments using E. coli cells that demonstrated an enhanced bacterial cytotoxicity for the SWNT-coated membranes. The SWNT membranes were observed to achieve up to 60% inactivation of bacteria attached to the membrane within 1 h of contact time. Our results suggest the potential of covalently bonded SWNTs to delay the onset of membrane biofouling during operation.
我们提出了一种创新的方法，将纳米材料的特性赋予到薄膜复合膜的表面。具体来说，通过将单壁碳纳米管 (SWNTs) 共价键合到膜表面，获得了杀菌性能。首先通过纯化和臭氧氧化对 SWNTs 进行改性，以增加其侧壁官能团、最大限度地提高细胞毒性，并实现在水溶液中的分散。开发了一种定制的反应方案，以利用手铸聚酰胺膜表面的固有部分，并与功能化的 SWNTs 形成共价酰胺键。该反应完全基于水，涉及激活膜和纳米材料的羧酸盐基团，以最大限度地与乙二胺反应。通过对膜进行超声处理后证实了 SWNTs 的存在，证实了 SWNTs 与膜表面之间的键的强度。对 SWNT 功能化表面的表征表明，获得了具有新型特性的膜，这些膜在水分离过程中继续表现出高性能。通过使用大肠杆菌细胞进行的实验证实了表面结合的抗菌 SWNTs 的存在，这些实验表明，SWNT 涂层膜对细菌的细胞毒性增强。观察到 SWNT 膜在接触 1 小时内可使附着在膜上的细菌失活达 60%。我们的结果表明，共价键合的 SWNTs 具有延迟膜生物污染在运行过程中发生的潜力。
