Mohammadi Aida, Daymond Mark R, Docoslis Aristides
Department of Chemical Engineering, Queen's University, Kingston, ON K7L3N6, Canada.
Department of Mechanical and Materials Engineering, Queen's University, Kingston, ON K7L3N6, Canada.
ACS Appl Mater Interfaces. 2020 Aug 5;12(31):34736-34745. doi: 10.1021/acsami.0c04122. Epub 2020 Jul 21.
There is an increasing demand for nuclear reactors, driven by the global need for low CO producing energy sources. The use of light (HO) or heavy water (DO) in a nuclear reactor environment produces radioactive tritiated heavy (HTO, DTO) water as an inevitable contaminant. Considering the need for tritiated water removal and also the high commercial value of purified water isotopes, technologies that can efficiently separate isotopic mixtures of water in nuclear reactors are highly desirable. This study presents an experimental approach for producing graphene oxide (GO) membranes and assessing their performance in the filtration of isotopic water mixtures. Specifically, using DO/HO mixtures as model systems, we investigate the effect of physicochemical properties of GO, as well as membrane preparation conditions on membrane filtration efficiency. We find that membranes assembled using larger GO platelets of lower oxidation level generally exhibit higher deuterated water (HDO, DO) rejection and filtrate flux. Moreover, membrane preparation conditions have a strong impact on the interlayer space between stacked GO nanoplatelets in the membrane, hence as a direct effect on filtration performance. Our experimental results also show a strong, nonmonotonic dependence of separation performance on operating temperature, as well as the existence of local temperature optima. Our work provides guidelines for simple and scalable preparation of GO membranes with very good mechanical stability, capable of achieving efficient separation of isotopic water.
受全球对低二氧化碳排放能源的需求推动，对核反应堆的需求日益增加。在核反应堆环境中使用轻水（H₂O）或重水（D₂O）会不可避免地产生放射性氚化重水（HTO、DTO）作为污染物。考虑到去除氚化水的需求以及纯净水同位素的高商业价值，能够有效分离核反应堆中水体同位素混合物的技术备受青睐。本研究提出了一种制备氧化石墨烯（GO）膜并评估其对同位素水混合物过滤性能的实验方法。具体而言，以D₂O/H₂O混合物为模型体系，我们研究了GO的物理化学性质以及膜制备条件对膜过滤效率的影响。我们发现，使用氧化程度较低的较大GO片层组装的膜通常表现出更高的重水（HDO、D₂O）截留率和滤液通量。此外，膜制备条件对膜中堆叠的GO纳米片层之间的层间距有很大影响，从而直接影响过滤性能。我们的实验结果还表明，分离性能对操作温度存在强烈的非单调依赖性，并且存在局部温度最优值。我们的工作为简单且可扩展地制备具有良好机械稳定性、能够实现同位素水高效分离的GO膜提供了指导。
