Torre-Celeizabal Andrea, Russo Francesca, Galiano Francesco, Figoli Alberto, Casado-Coterillo Clara, Garea Aurora
Department of Chemical and Biomolecular Engineering, Universidad de Cantabria, Av. Los Castros s/n, 39005 Santander, Spain.
Institute on Membrane Technology (CNR-ITM), Via P. Bucci 17/C, 87036 Rende (CS), Italy.
ACS Sustain Chem Eng. 2025 Jan 16;13(3):1253-1270. doi: 10.1021/acssuschemeng.4c07538. eCollection 2025 Jan 27.
Although membrane technology is widely used in different gas separation applications, membrane manufacturers need to reduce the environmental impact during the membrane fabrication process within the framework of the circular economy by replacing toxic solvents, oil-based polymers, and such by more sustainable alternatives. These include environmentally friendly materials, such as biopolymers, green solvents, and surfactant free porous fillers. This work promotes the use of environmentally sustainable and low toxic alternatives, introducing the novel application of cellulose acetate (CA) as a biopolymer in combination with dimethyl carbonate (DMC) as a greener solvent and different inorganic fillers (Zeolite-A, ETS-10, AM-4 and ZIF-8) prepared without the use of toxic solvents or reactants. Hansen Solubility Parameters were used to confirm the polymer-solvent affinity. Pure CA and mixed matrix membranes were characterized regarding their hydrophilicity by water uptake and contact angle measurements, thermal stability by TGA, mechanical resistance, ATR-FTIR and scanning electron microscopy before evaluating the gas separation performance by single gas permeability of N, CH, and CO. Conditioning of the CA membranes is observed causing reduction of the CO permeability values from 12,600 Barrer for the fresh 0.5 wt % ETS-10/CA membrane to 740 Barrer for the 0.5 wt % ZIF-8/CA membranes, corresponding to 24% and 4.2% reductions in CO/CH selectivity and 30% and 24% increase in CO/N selectivity for the same membranes. The structure-relationship was evaluated by phenomenological models which are useful at low filler loading considering flux direction and particle shape and size but still fail to explain the interactions between the DMC green solvent and CA matrix and fillers that are influencing gas transport performance different than other CA membranes.
尽管膜技术广泛应用于不同的气体分离应用中，但膜制造商需要在循环经济框架内，通过用更可持续的替代品取代有毒溶剂、油基聚合物等来减少膜制造过程中的环境影响。这些替代品包括环保材料，如生物聚合物、绿色溶剂和无表面活性剂的多孔填料。这项工作推广使用环境可持续且低毒的替代品，介绍了醋酸纤维素（CA）作为生物聚合物与碳酸二甲酯（DMC）作为更绿色的溶剂以及不同无机填料（沸石-A、ETS-10、AM-4和ZIF-8）的新应用，这些无机填料是在不使用有毒溶剂或反应物的情况下制备的。使用汉森溶解度参数来确认聚合物-溶剂的亲和力。在通过N₂、CH₄和CO₂的单气体渗透率评估气体分离性能之前，对纯CA膜和混合基质膜的亲水性进行了吸水率和接触角测量表征，热稳定性通过热重分析（TGA）表征，机械抗性通过衰减全反射傅里叶变换红外光谱（ATR-FTIR）和扫描电子显微镜表征。观察到CA膜的老化导致CO₂渗透率值从新鲜的0.5 wt% ETS-10/CA膜的12,600巴雷尔降低到0.5 wt% ZIF-8/CA膜的740巴雷尔，对于相同的膜，CO₂/CH₄选择性分别降低了24%和4.2%，CO₂/N₂选择性分别增加了30%和24%。通过现象学模型评估了结构-关系，这些模型在低填料负载下考虑通量方向、颗粒形状和尺寸时是有用的，但仍然无法解释DMC绿色溶剂与CA基质和填料之间的相互作用，这些相互作用对气体传输性能的影响与其他CA膜不同。
