氟硅烷联合紫外照射改性陶瓷膜在VMD海水淡化中的应用

发布时间：2018-05-24 12:15

本文选题：陶瓷膜 + 紫外接枝改性　；参考：《北京化工大学》2015年硕士论文

【摘要】：膜蒸馏是一项新型的海水淡化技术,由于受到膜蒸馏用膜种类少、制膜成本高、过程传质阻力大、渗透通量相对较小影响,其工业化应用尚未实现。本文针对膜蒸馏过程用膜的特点,使用长链氟硅烷1H,1H,2H,2H-全氟辛基三氯硅烷(PFAS)和1H,1H,2H,2H-全氟癸基三乙氧基硅烷(PFDS)做改性剂,采用紫外接枝法对平均孔径200nm的A1203陶瓷膜进行疏水改性,对改性过程中和改性完成后的膜片进行表征和分析：疏水改性之后膜表面均匀分布着针状和簇状的微观结构,XPS、FT-IR等检测结果表明此结构为低表面能的有机聚合物薄膜；疏水A1203陶瓷膜表面的接触角最高可以达到159°,疏水性能良好。同时本论文还详细研究了预处理剂、溶剂、光引发剂、改性剂等条件对紫外接枝改性过程的影响。实验利用经过紫外接枝改性的疏水陶瓷膜,采用真空膜蒸馏法对模拟海水(NaCl水溶液)进行脱盐淡化实验,对该过程的主要操作条件做了系统研究,同时评价了疏水改性后陶瓷膜的性能。结果表明：在适宜的操作条件下,VMD脱盐淡化过程渗透通量达27.28kg.m-2.h-1,截留率达到99.99%。说明此方法改性的陶瓷膜可以较好地应用于VMD过程且效果良好。最后一部分研究实验,选用商业化聚丙烯膜,使用真空膜蒸馏法对八种亲水性离子液体水溶液进行浓缩净化,对过程中的操作条件进行了分析研究,结果表明：提高进料温度、进料流速和渗透侧真空度,渗透通量增大；而进料液浓度增大,渗透通量则会减小；全部实验的回收率始终保持在99.5%以上,说明操作条件对回收率影响不大,回收率主要受到膜性能和溶液性质的影响；实验证明真空膜蒸馏法进行离子液体的浓缩回收是可行的且效果较好。
[Abstract]:Membrane distillation is a new seawater desalination technology. Due to the lack of membrane species, high membrane cost, high mass transfer resistance and relatively small permeation flux, the industrial application of membrane distillation has not been realized. According to the characteristics of membrane used in membrane distillation process, the A1203 ceramic membrane with average pore size (200nm) was modified by UV grafting method using long chain fluorosilane 1H 1H 1H 2 H 2 H 2 H perfluorooctyl trichlorosilane (PFASS) and 1H 1 H 1 H 2 H 2 H perfluorodecyl triethoxysilane (PFDS) as modifiers, and the A1203 ceramic membrane with average pore size (200nm) was modified by UV grafting method. The film was characterized and analyzed in the process of modification and after modification: after hydrophobic modification, the surface of the membrane was evenly distributed in needle shape and cluster shape, and the results showed that the structure was an organic polymer film with low surface energy. The contact angle of the surface of the hydrophobic A1203 ceramic film is up to 159 掳, and the hydrophobic property is good. At the same time, the effects of pretreatment agent, solvent, photoinitiator and modifier on the process of UV grafting modification were studied in detail. The desalination and desalination experiments were carried out by using ultraviolet modified hydrophobic ceramic membrane and vacuum membrane distillation. The main operating conditions of the process were systematically studied. The properties of the hydrophobic modified ceramic membrane were also evaluated. The results showed that the osmotic flux of VMD desalination was 27.28 kg 路m ~ (-2) h-1 and the rejection rate was 99.99%. The results show that the ceramic membrane modified by this method can be used in VMD process with good effect. In the last part of the experiment, the commercial polypropylene membrane was selected to concentrate and purify eight kinds of hydrophilic ionic liquid aqueous solution by vacuum membrane distillation. The operating conditions were analyzed and studied. The results showed that the feed temperature was increased. The permeation flux increases with the feed flow rate and the vacuum degree of the permeable side, while the permeation flux decreases with the increase of the feed concentration, and the recovery rate of the whole experiment remains above 99.5%, which indicates that the operating conditions have little effect on the recovery rate. The recovery rate is mainly affected by the properties of membrane and solution, and it is proved by experiments that the concentration and recovery of ionic liquids by vacuum membrane distillation is feasible and effective.
【学位授予单位】：北京化工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P747.1;TQ051.893

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