Low temperature thermally induced phase separation (LT-TIPS) of chitosan solution was developed to fabricate porous chitosan membranes (p-CSMs), which were composed of short nanofibers with diameter of 40–60 nm. Compared to the conventional acetic acid/water solvent, a mixed solvent of acetic acid/ethanol/water was used to prepare chitosan solution. The effect of solvent composition, quenching temperature and time, and coagulant on the p-CSM morphology were systematically explored. The optimum conditions for fabricating p-CSM was to quench 2% chitosan/2% acetic acid in water/ethanol (70/30) at −20 °C for 12 h, followed by coagulating in 1% Na₂CO₃ in water/ethanol (50/50). The p-CSM was an effective adsorbent for Cu²⁺ and had a Langmuir adsorption capacity of 2.57 mmol/g, which is close to the adsorption capacity of natural and electrospun chitosan nanofibers. The p-CSM maintained 90% adsorption efficiency for Cu²⁺ even after six cycles.

中文翻译：

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低温热诱导相分离法制备纳米纤维组成的壳聚糖多孔膜及其对Cu ^2+的吸附行为

开发了壳聚糖溶液的低温热诱导相分离（LT-TIPS），以制造多孔壳聚糖膜（p-CSMs），该膜由直径为40-60 nm的短纳米纤维组成。与常规的乙酸/水溶剂相比，使用乙酸/乙醇/水的混合溶剂制备壳聚糖溶液。系统地研究了溶剂组成，淬火温度和时间以及凝结剂对p-CSM形态的影响。制备p-CSM的最佳条件是在-20°C下于水/乙醇（70/30）中淬灭2％壳聚糖/ 2％乙酸12小时，然后在1％Na ₂ CO ₃于水中/乙醇（50/50）。p-CSM是Cu ²⁺的有效吸附剂的朗缪尔（Langmuir）吸附容量为2.57 mmol / g，接近天然和静电纺丝的壳聚糖纳米纤维的吸附容量。即使经过6个循环，p-CSM仍能保持90％的Cu ²⁺吸附效率。