本文選題：聚丙烯腈　切入點(diǎn)：層層組裝　出處：《東華大學(xué)》2017年碩士論文

【摘要】：正滲透(Forward osmosis,FO)技術(shù)作為一種新型膜分離技術(shù),在污水深度處理領(lǐng)域具有很大的應(yīng)用潛力,正滲透膜的制備是正滲透技術(shù)研究的熱點(diǎn)。本研究通過相轉(zhuǎn)化法制備出粗糙度較低、滲透通量較高的聚丙烯腈(PAN)支撐層,在支撐層表面考察界面聚合的次數(shù)和碳納米管濃度對所制備復(fù)合正滲透膜性能的影響,以提高正滲透膜的分離性能,并采用復(fù)合正滲透膜對二沉池出水的深度處理效果進(jìn)行了探討,論文結(jié)果可為城市污水的深度處理提供技術(shù)參考。首先,利用相轉(zhuǎn)化法制備聚丙烯腈(PAN)基膜,對其堿性水解后,分別置于聚乙烯亞胺(PEI)、聚丙烯酸(PAA)溶液中,進(jìn)行接枝反應(yīng)制得PAN-PEI/PAA支撐層。分別采用掃描電鏡、原子力顯微鏡進(jìn)行表面形貌分析,傅里葉紅外光譜、Zeta電位、接觸角和拉伸強(qiáng)度對支撐層結(jié)構(gòu)進(jìn)行分析,并測的支撐層純水通量為175.2 L/m2·h。其次,采用層層組裝技術(shù)對界面聚合法進(jìn)行優(yōu)化,考察界面聚合次數(shù)對聚酰胺復(fù)合膜結(jié)構(gòu)性能的影響。分析可知:隨著界面聚合次數(shù)的增加,活性分離層致密性逐漸增加,粗糙度逐漸增大;接觸角、Zeta電位逐漸降低,機(jī)械性能逐漸增強(qiáng);分離性能測試可知,隨著界面聚合次數(shù)的增加,反滲透水通量逐漸減小,鹽截留率(R)逐漸增大,FO水通量(Jw)和鹽逆向通量(Js)均逐漸降低,但鹽逆向通量與水通量比(Js/Jw)呈現(xiàn)先減小后增大的趨勢。結(jié)果表明二次界面聚合所制備的復(fù)合膜的正滲透性能最好,Jw達(dá)到16.97L/m2·h,Js為6.02g/m2·h,Js/Jw為0.35 g/L。再次,為改善正滲透膜的性能,將碳納米管(CNTs)添加至復(fù)合膜活性分離層中,考察正滲透膜性能的變化。研究可知:隨著CNTs濃度的增加,活性分離層出現(xiàn)絮狀物質(zhì)且逐漸增多,粗糙度逐漸增大;紅外分析和XPS分析表明CNTs成功嵌入正滲透膜活性分離層中;親水性能隨著CNTs含量的增加而增大。采用正滲透測試裝置對復(fù)合正滲透膜的分離性能進(jìn)行分析可知,隨著CNTs濃度的增大,水通量值隨之增大。當(dāng)CNTs的濃度為0.2 wt%時(shí),制備正滲透膜的分離性能較好,Js可以達(dá)到25.14 L/m2·h,Jw為8.64 g/m2·h,Js/Jw值為0.37 g/L,CNTs添加量為0.2 wt%條件下制備的正滲透膜與三種商業(yè)膜(CTA-ES、TFC-ES、CTA-NW)進(jìn)行對比,可知制備的正滲透膜在短時(shí)間運(yùn)行條件下,水通量和正滲透分離性能均優(yōu)于三種商業(yè)膜。最后,考察二次界面聚合制備的正滲透膜(TFC)、加入碳納米管后正滲透膜(TFN)對二沉池出水中污染物的截留效果以及正滲透性能變化。結(jié)果表明TFN的水通量大于TFC的水通量,但TFC正滲透膜對污染物的截留效果好于TFN正滲透膜,兩者對于TOC、TP和TN的截留效果達(dá)到60%之上,對于氨氮的截留率在50%左右。
[Abstract]:As a new membrane separation technology, forward osmosis FOO (forward osmosis) technology has great application potential in the field of advanced wastewater treatment. The preparation of forward osmotic membrane is a hot topic in the research of forward osmotic technology.The polyacrylonitrile (pan) support layer with low roughness and high permeation flux was prepared by phase inversion method. The effects of interfacial polymerization times and carbon nanotube concentration on the properties of the composite membrane were investigated on the surface of the support layer.In order to improve the separation performance of normal-osmotic membrane, the effect of advanced treatment of secondary sedimentation tank effluent was discussed by using composite normal-osmotic membrane. The results of this paper can provide technical reference for advanced treatment of municipal sewage.Firstly, the polyacrylonitrile (pan) base film was prepared by phase inversion method. After alkaline hydrolysis, the polyacrylonitrile (pan) substrate was prepared by grafting reaction in the solution of polyimide (PEI) and polyacrylic acid (PAA) respectively.The surface morphology was analyzed by scanning electron microscope (SEM) and atomic force microscope (AFM). The structure of the support layer was analyzed by Fourier transform infrared spectroscopy (FTIR) potential, contact angle and tensile strength. The pure water flux of the support layer was measured to be 175.2 L/m2 / h.Secondly, the interfacial polymerization method was optimized by layer-by-layer assembly technique, and the influence of interfacial polymerization times on the structure and properties of polyamide composite membrane was investigated.The results show that with the increase of interfacial polymerization times, the densification and roughness of the active separation layer increase gradually, the Zeta potential of contact angle decreases and the mechanical properties increase.With the increase of interfacial polymerization times, the reverse osmosis water flux decreases, the salt rejection ratio (R) increases, the water flux of FO and the reverse flux of salt decrease gradually, but the ratio of reverse flux of salt to water flux decreases first and then increases.The results show that the composite membranes prepared by the secondary interfacial polymerization have the best forward osmotic properties (J w = 16.97L/m2 HN / J s = 6.02g/m2 HS / J w = 0.35 g / L).Thirdly, in order to improve the performance of the membrane, CNTswas added to the active separation layer of the composite membrane, and the change of the performance of the membrane was investigated.The results showed that with the increase of CNTs concentration, flocculants appeared in the active separation layer, and the roughness increased gradually, and the IR and XPS analysis showed that CNTs was successfully embedded in the active separation layer of the normal osmotic membrane.The hydrophilic energy increases with the increase of CNTs content.The separation performance of composite normal osmotic membrane was analyzed by using the normal osmotic test device. The water flux increased with the increase of CNTs concentration.褰揅NTs鐨勬祿搴︿負(fù)0.2 wt%鏃，

本文編號：1702743