Quellmalz Arne, Mihranyan Albert
Nanotechnology and Functional Materials, Department of Engineering Sciences, Uppsala University, Box 534, 75121 Uppsala, Sweden.
ACS Biomater Sci Eng. 2015 Apr 13;1(4):271-276. doi: 10.1021/ab500161x. Epub 2015 Mar 5.
This article explores the effect of cross-linking of nanocellulose with citric acid for the development of novel paper filters for potential application within nanofiltration, including sterile (virus) filtration. Cladophora cellulose paper sheets were cross-linked by first soaking in 16 wt % citric acid in the presence of 1 wt % sodium hypophosphate overnight and then curing at 160 °C for 10 min in a hot-press. The cross-linked paper filter samples were then characterized with FTIR, AFM, N gas adsorption, and tensile strength analysis (dry and wet strength). The particle retention properties were further studied with respect to filtering of 20 nm Au nanoparticles with SEM and comparing the UV absorbance intensity of the starting solution and the filtrate. The wet strength of the paper filter was greatly improved following the cross-linking, although in the dry state, the paper becomes brittle. The improved wet strength of the paper filter enables increasing the pressure gradient applied for filtration without compromising the integrity of the filter. This is the first report in which a fully nature-derived paper filter is capable of removing tracer particles as small as 20 nm. It is concluded that citric acid cross-linking of nanocellulose is beneficial for developing paper based sterile (virus) removal industrial filters.
本文探讨了纳米纤维素与柠檬酸交联对开发新型纸质过滤器的影响，该过滤器有望应用于纳滤，包括无菌（病毒）过滤。将枝管藻纤维素纸片进行交联，方法是先在含有1 wt%次磷酸钠的16 wt%柠檬酸中浸泡过夜，然后在热压机中于160°C固化10分钟。然后用傅里叶变换红外光谱（FTIR）、原子力显微镜（AFM）、氮气吸附和拉伸强度分析（干强度和湿强度）对交联后的纸质过滤器样品进行表征。通过扫描电子显微镜（SEM）对20 nm金纳米颗粒的过滤情况进行研究，并比较起始溶液和滤液的紫外吸光度强度，进一步研究颗粒保留特性。交联后纸质过滤器的湿强度得到了极大提高，不过在干燥状态下，纸张会变脆。纸质过滤器湿强度的提高使得在不损害过滤器完整性的情况下能够增加过滤时施加的压力梯度。这是首次报道完全由天然材料制成的纸质过滤器能够去除小至20 nm的示踪颗粒。得出的结论是，纳米纤维素的柠檬酸交联有利于开发基于纸张的无菌（病毒）去除工业过滤器。
