改性聚偏氟乙烯超滤膜的制备及处理乳化含油废水性能研究

发布时间：2018-02-27 12:43

本文关键词： 乳化含油废水聚偏氟乙烯超滤膜氧化石墨烯抗污染改性　出处：《西安建筑科技大学》2017年硕士论文　论文类型：学位论文

【摘要】：冶金、化工、机械加工等行业都会产生大量的含油废水,若对含油废水不进行处理直接排放,其流入海洋湖泊等水体中则严重影响人体健康及动植物的生长。乳化含油废水是含油废水中最难处理的一种,油滴表面双电层体系使其性质非常稳定,冷轧、金属萃取及石油开采过程中则直接产生大量的乳化含油废水。超滤膜分离技术与传统的化学破乳法相比,分离效率高、操作简便、油品可回收。然而油滴在膜表面和膜孔内吸附沉积造成的膜污染严重制约了超滤膜在实际处理含油废水工业中的应用。氧化石墨烯(GO)因其高的比表面积和丰富的亲水性基团被广泛用于膜材料改性来提高膜的抗污染性能。但是GO在膜基质中极易聚集,这不但使GO优异性能得不到充分的发挥,而且也会对膜结构和性能产生不利影响。本论文选取络氨酸(Tyr)、N-(三甲氧基硅丙基)乙二胺三乙酸钠(EDTS)及壳聚糖(CS)三种亲水性物质,在合适的条件下与GO发生反应制备了不同的功能化氧化石墨烯(F-GO),并且对GO功能化前后的化学成分、形貌结构及分散性进行了检测分析。结果表明经Tyr、EDTS及CS功能化后,GO规则的片层累积结构被破坏,形成了一种不同片层朝向的无序结构,减弱了GO片层之间的π-π相互作用,增强了其分散性。本论文还通过共混的方式制备了Tyr-GO、EDTS-GO及CS-GO改性的聚偏氟乙烯(PVDF)超滤膜,系统考察了不同F-GO添加量对PVDF超滤膜结构及性能的影响。结果表明PVDF超滤膜的亲水性、孔隙率、水通量随着F-GO添加量的增加呈现出先增大后减小的趋势。Tyr-GO最佳添加量为1.5%,此时膜的纯水通量达到684.49 L/m2·h,油截留率达到94.63%;EDTS-GO的最佳添加量为0.5%,此时膜的纯水通量达到711.23 L/m2·h,油截留率达到93.87%;CS-GO的最佳添加量为0.6%,此时膜的纯水通量达到737.18 L/m2·h,油截留率达到91.67%。本论文进一步对F-GO改性的PVDF超滤膜和GO改性的PVDF超滤膜以及纯的PVDF超滤膜处理乳化含油废水的性能进行了研究。结果表明在处理乳化含油废水过程中,Tyr-GO的添加使纯PVDF膜的通量提高了84.47%,使GO/PVDF膜的通量提高了38.46%;EDTS-GO的添加使纯PVDF膜的通量提高了78.96%,使GO/PVDF膜的通量提高了47.83%;CS-GO的添加使纯PVDF膜的通量提高了80%,使GO/PVDF膜的通量提高了45.16%。而且Tyr-GO、EDTS-GO及CS-GO改性的PVDF膜的通量恢复率和可逆通量衰减率明显高于PVDF膜和GO改性的PVDF膜,这表明经Tyr、EDTS及CS修饰后的GO改性的PVDF膜比未经修饰的GO改性的PVDF膜具有更强的处理乳化含油废水的性能。
[Abstract]:Metallurgical, chemical, mechanical and other industries will produce a large amount of oily wastewater. If the oily wastewater is not treated directly, The emulsified oily wastewater is one of the most difficult to treat in the oily wastewater, and the double-layer system of oil droplet surface makes its properties very stable and cold rolled. In the process of metal extraction and petroleum extraction, a large amount of emulsified oily wastewater is produced directly. Compared with the traditional chemical demulsification method, the ultrafiltration membrane separation technology has high separation efficiency and simple operation. Oil can be recovered. However, membrane fouling caused by adsorption and deposition of oil droplets on membrane surface and in membrane pore seriously restricts the application of ultrafiltration membrane in the treatment of oily wastewater. Hydrophilic groups are widely used in the modification of membrane materials to improve the antifouling properties of membranes. This not only makes the excellent performance of go not fully play, but also has a negative impact on the structure and properties of the membrane. In this paper, three hydrophilic substances, N-trimethoxysilylpropyl) ethylenediamine triacetate (EDTS) and chitosan (CSS), are selected as hydrophilic substances. Different functionalized graphene oxide F-GOA was prepared by reaction with go under suitable conditions, and the chemical constituents before and after go functionalization were studied. The morphology and dispersity were examined and analyzed. The results showed that the accumulated lamellar structure of the go rule was destroyed after Tyr-EDTS and CS functionalization, resulting in a disordered structure with different lamellar orientation, which weakened the 蟺-蟺 interaction between go lamellae. In this thesis, Tyr-GOG EDTS-GO and CS-GO modified polyvinylidene fluoride (PVDF) ultrafiltration membranes were prepared. The effects of different F-GO contents on the structure and properties of PVDF ultrafiltration membranes were systematically investigated. The results showed that the PVDF ultrafiltration membranes were hydrophilic. Porosity, With the increase of F-GO addition, the water flux increased first and then decreased. The optimum addition amount of Tyr-GO was 1.5. The pure water flux of the membrane reached 684.49 L / m ~ 2 路h, the oil retention reached 94.63% EDTS-GO and the optimum addition amount was 0.5. The pure water flux of the membrane reached 711.23. L- / m ~ 2 路h, the oil rejection rate reached 93.87g / L ~ (S-GO) and the optimum addition amount was 0.6.The pure water flux of the membrane was 737.18 L / m ~ (2) 路h, and the oil rejection rate was 91.67. In this thesis, F-GO modified PVDF ultrafiltration membrane, go modified PVDF ultrafiltration membrane and pure PVDF ultrafiltration membrane were further used to treat emulsion. The results showed that the addition of Tyr-GO increased the flux of pure PVDF membrane by 84.47, and the flux of GO/PVDF membrane increased by 38.46EDTS-GO, and the flux of pure PVDF membrane increased by 78.96%. The flux of GO/PVDF membrane increased by 47.83%, the flux of pure PVDF membrane increased by 80% and the flux of GO/PVDF membrane increased by 45.16.The flux recovery rate and reversible flux attenuation rate of PVDF membrane modified by Tyr-GOEDTS-GO and CS-GO were obviously higher than those of PVDF membrane and PVDF membrane modified by go. The results show that the modified PVDF membrane modified by Tyrn EDTS and CS has better performance in treating emulsified oily wastewater than the PVDF membrane modified by PVDF without modification.
【学位授予单位】：西安建筑科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ051.893;X703

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