二元醇共价交联羧基化石墨烯复合膜和正丁醇脱水性能

以二元醇(乙二醇、1,3-丙二醇和1,4-丁二醇)为交联剂，通过抽滤的方式在涂覆盐酸多巴胺的聚醚砜(PES)支撑层上制备了共价交联的羧基化石墨烯/聚醚砜(CG/PES)复合膜。稳定性测试证明盐酸多巴胺的涂覆和二元醇的交联显著提高了分离层和支撑层以及CG纳米片间的结合力。采用扫描电子显微镜、X射线衍射仪、X射线光电子能谱仪和水接触角测试仪对复合膜的物化性质和微观形貌进行了表征。结果表明，所得复合膜的分离层连续无缺陷，厚度在60～64nm之间。二元醇与CG纳米片上的羧基成功发生反应，将CG纳米片锚固在一起。交联剂的引入没有大幅降低亲水性且实现了对分离层层间距的有效调控，随二元醇分子尺寸增加，所得复合膜的层间距由0.761nm提高到0.778nm。CG/PES复合膜对正丁醇/水混合物具有优良的渗透汽化分离性能。在料液温度为50℃、料液中水的质量分数为10%时，三种交联剂所得复合膜的渗透通量分别达到0.79kg/(m²·h)、0.87kg/(m²·h)和0.96kg/(m²·h)，而分离因子比未交联的复合膜高一个数量级。15天的...

Carboxyl graphene composite membranes covalently crosslinked with diols and the n-butanol dehydration properties

Covalently crosslinked carboxyl graphene/polyethersulfone (CG/PES) composite membranes were prepared by suction filtration. Polyethersulfone (PES) support was coated with dopamine hydrochloride. Diols(ethylene glycol, 1,3-propylene glycol and 1,4-butanediol) were used as crosslinking agents. The stability test showed that the coated dopamine hydrochloride improved the adhesion between the separation layer and the support layer. The diol crosslinking structure ensured the stability of the CG separation layer. The physicochemical properties and micro morphology of the composite membranes were characterized by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and water contact angle tester. The results indicated that the separation layer of the composite membrane was continuous and defect-free, and the thickness ranged from 60nm to 64nm. The diol reacted successfully with the carboxyl groups on the CG nanosheets and anchored the CG nanosheets together. The introduction of crosslinking agents did not significantly reduce the membrane hydrophilicity and realized the effective regulation of the d-spacing. With the increase of diol molecular size, the d-spacing of the composite membrane increased from 0.761nm to 0.778nm. CG/PES composite membrane exhibited excellent pervaporation separation performance for n-butanol/water mixture. When the feed temperature was 50℃ and the water mass fraction in feed was 10%, the permeation flux of the composite membrane obtained from the three crosslinking agents reached to 0.79kg/(m²·h), 0.87kg/(m²·h) and 0.96kg/(m²·h), respectively. The separation factor was one order of magnitude higher than that of the non-crosslinked composite membrane. The 15 day stability testing results showed that the separation performance of as-prepared composite membrane had no significant change and can meet the requirements of pervaporation application.