本文選題：PVDF分離膜　切入點(diǎn)：平板刮膜機(jī)　出處：《華南理工大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：聚偏氟乙烯(PVDF)是半結(jié)晶性聚合物,具有良好的耐腐蝕性、化學(xué)穩(wěn)定性和優(yōu)異的成膜性能,廣泛應(yīng)用于膜分離技術(shù)領(lǐng)域,但PVDF分離膜易被濾液中有機(jī)物污染等缺點(diǎn)制約了它更多領(lǐng)域的應(yīng)用。PVDF分離膜的性能和刮膜設(shè)備及鑄膜液配方息息相關(guān),因此通過改進(jìn)制膜設(shè)備、完善鑄膜液配方以及膜光催化改性來使PVDF分離膜性能更加優(yōu)異具有重要的意義。本課題首先完成了實(shí)驗(yàn)室用平板刮膜機(jī)的設(shè)計(jì),利用該設(shè)備制備出PVDF分離膜和Ti O2-PVDF雜化分離膜,并對優(yōu)化出的雜化PVDF膜進(jìn)行光催化改性。主要研究內(nèi)容如下:首先,針對實(shí)驗(yàn)室用中小型平板刮膜機(jī)制膜精度不高和制膜效率較低的不足,通過精確調(diào)節(jié)旋鈕來調(diào)節(jié)分離膜的厚度,同時采用凝膠水浴箱和導(dǎo)輥來輔助完成連續(xù)刮膜過程,進(jìn)一步利用電機(jī)和在線測速調(diào)節(jié)裝置來保證刮膜線速度的恒定,保證分離膜制品的精度。利用自行設(shè)計(jì)的刮膜機(jī)制備PVDF分離膜,探究了PVDF固含量和聚乙二醇-6000(PEG-6000)固含量對分離膜性能的影響;研究了不同Ti O2固含量對分離膜性能的影響,優(yōu)化出Ti O2-PVDF雜化分離膜;自行制備了Ti O2溶膠,并對比了直接添加Ti O2、添加Ti O2/分散劑和添加Ti O2溶膠對分離膜性能的影響;最后對最優(yōu)雜化膜進(jìn)行光催化改性,探究了不同光照強(qiáng)度、不同光照時間、待濾液PH值和待濾液濃度對光催化改性分離膜自清潔性能的影響。研究結(jié)果表明:1)自行研制的科研用平板刮膜機(jī)膜厚可控精度高,膜厚可調(diào)節(jié)精度為1um,最大刮膜速度為2.0 m/min,凝膠水浴時間可控;2)當(dāng)PVDF的固含量為22wt.%,PEG-6000固含量為12.5wt.%時,純PVDF擁有較好的綜合性能,其中純水通量為1270L/(m2?h?bar),截留率為68%。3)當(dāng)Ti O2固含量為0.5wt.%時,鑄膜液成膜性能良好,改性分離膜較純PVDF分離膜在熱穩(wěn)定性、親水性等方面的均有一定程度的提升。通過制備Ti O2溶膠可以在一定程度上改善Ti O2在鑄膜液中的分散性,添加溶膠態(tài)Ti O2的分離膜表面Ti元素重量百分比為4.66%,為三種改性分離膜里面最高。4)通過光催化紫外輻照實(shí)驗(yàn),Ti O2光催化改性分離膜相較純PVDF分離膜呈現(xiàn)出一定的自清潔特性。在1m W/cm2的紫外輻照下,16h時三種改性分離膜的通量恢復(fù)均比純PVDF高19%以上;1m W/cm2的光照強(qiáng)度為此種Ti O2改性分離膜的最佳自清潔光照強(qiáng)度;待濾液PH=7時,Ti O2光催化改性分離膜的光催化改性效能最優(yōu);當(dāng)腐殖酸濃度為0.5mg/L時,分離膜的通量衰減最小,自清潔效果最佳。
[Abstract]:Polyvinylidene fluoride PVDF (PVDF) is a semi-crystalline polymer with good corrosion resistance, chemical stability and excellent film-forming properties. It is widely used in membrane separation technology. However, the disadvantages of PVDF separation membrane being easily polluted by organic matter in filtrate restrict its application in many fields. The performance of membrane separation membrane is closely related to the scraping equipment and the formulation of cast membrane solution, so the membrane preparation equipment is improved. It is of great significance to improve the formulation of cast membrane liquid and the modification of membrane photocatalysis to improve the performance of PVDF separation membrane. Firstly, the design of lab flat scraping machine was completed, and the PVDF separation membrane and TIO _ 2-PVDF hybrid separation membrane were prepared by this equipment. The main research contents are as follows: first of all, aiming at the shortcomings of low precision and low efficiency of membrane preparation, the mechanism membrane of small and medium scale flat scraping used in laboratory is not high, and the photocatalytic modification of the optimized hybrid PVDF membrane is carried out. The thickness of the separation membrane is adjusted by adjusting the knob accurately, and the continuous scraping process is completed with the help of gel bath box and guide roll. Furthermore, the constant wiping speed is ensured by using the motor and the on-line speed adjusting device. The effect of solid content of PVDF and PEG-6000) on the performance of separation membrane was studied, and the effect of solid content of TIO _ 2 on the performance of membrane was studied. TIO _ 2-PVDF hybrid separation membrane was optimized, TIO _ 2 sol was prepared, and the effects of direct addition of TIO _ 2, TIO _ 2 / dispersant and TIO _ 2 sol on the performance of separation membrane were compared. The effects of different light intensity, different illumination time, PH value and concentration of filtrate on the self-cleaning performance of photocatalytic modified membrane were investigated. When the solid content of PVDF is 22 wt. and PEG-6000 solid content is 12.5 wt.%, the pure PVDF has better comprehensive properties, in which the pure water flux is 1270 L / m ~ 2? H? When the solid content of TIO _ 2 is 0.5 wt.%, the film formation performance of the cast liquid is good, and the thermal stability of the modified membrane is better than that of the pure PVDF separation membrane. The hydrophilicity of TIO _ 2 sol can be improved to some extent by the preparation of TIO _ 2 sol, and the dispersion of TIO _ 2 in casting solution can be improved to some extent. The weight percentage of Ti on the surface of the membrane was 4.66, which was the highest in the three kinds of modified membranes. The photocatalytic ultraviolet irradiation experiment showed that the phase of TIO _ 2 photocatalytic separation membrane was higher than that of pure PVDF membrane. The self-cleaning characteristics: the flux recovery of the three modified membranes under UV irradiation of 1m W / cm ~ 2 for 16 h is more than 19% m W / cm ~ 2 higher than that of pure PVDF, which is the best self-cleaning illumination intensity of the modified membranes. When the concentration of humic acid was 0.5 mg / L, the flux of separation membrane was the least, and the self-cleaning effect was the best.
【學(xué)位授予單位】：華南理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TQ051.893

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