Abstract Biogas can be used as an alternative energy source in place of conventional fossil fuels. However, for this to happen, it is necessary to optimize biogas production as well as improve the biogas quality. Crystalline nanocellulose (CNC) has excellent mechanical properties as well as a high moisture uptake ability. These properties make CNC a promising candidate to be used as an additive in polyvinyl alcohol (PVA)-facilitated transport membranes (FTMs). The overall objective of this work is to develop CNC/PVA nanocomposite membranes for enhancing the biogas quality through CO2 capture. The effects of CNC concentration and the pH of the casting solution are investigated to optimize CO2/CH4 separation. Membrane characterization shows that the addition of CNC affects the degree of swelling, crystallinity and thickness of the resulting membranes, while permeation testing showed that the permeance and selectivity for CO2 increased with the addition of CNC. Membranes produced with 1% CNC and a casting suspension at pH 10 gave the best results under the given set of conditions. The maximum permeance achieved by the formulated nanocomposite membranes was 0.29 m3(STP)/(m2-h-bar), while the selectivity of CO2 over CH4 was 43. It was also observed that increasing the feed gas pressure deteriorated the membrane performance.

中文翻译：

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用于在高压下分离 CO 2 /CH 4 的纤维素纳米晶体/PVA 纳米复合膜

摘要 沼气可作为替代传统化石燃料的替代能源。然而，要做到这一点，就必须优化沼气生产并提高沼气质量。结晶纳米纤维素 (CNC) 具有优异的机械性能以及高吸湿能力。这些特性使 CNC 成为有希望用作聚乙烯醇 (PVA) 促进传输膜 (FTM) 添加剂的候选者。这项工作的总体目标是开发 CNC/PVA 纳米复合膜，通过 CO2 捕获来提高沼气质量。研究了 CNC 浓度和浇铸溶液 pH 值的影响，以优化 CO2/CH4 分离。膜表征表明，CNC 的加入会影响溶胀程度，所得膜的结晶度和厚度，而渗透测试表明 CO2 的渗透性和选择性随着 CNC 的加入而增加。在给定的一组条件下，使用 1% CNC 和浇铸悬浮液在 pH 值为 10 下生产的膜得到最佳结果。配制的纳米复合膜实现的最大渗透率为 0.29 m3(STP)/(m2-h-bar)，而 CO2 对 CH4 的选择性为 43。还观察到增加进料气体压力会降低膜性能。