本文選題：納濾膜 + 聚丙烯腈　； 參考：《東華大學(xué)》2017年碩士論文

【摘要】：膜分離技術(shù)具有分離高效、濃縮、提純和凈化等優(yōu)點(diǎn)。近年來,隨著人們對(duì)水資源需求和用水標(biāo)準(zhǔn)的日益增長(zhǎng),污水處理的壓力日益增加,納濾膜的研究得到了極大促進(jìn)。納濾膜的分離性能介于超濾膜和反滲透膜之間,主要用于分離分子量在200-2000之間的小分子物質(zhì),被廣泛用于硬水軟化、印染廢水處理、食品工業(yè)和制藥工業(yè)等領(lǐng)域。傳統(tǒng)制備納濾膜所采用的非溶劑致相分離法和復(fù)合法等易導(dǎo)致膜強(qiáng)度低、結(jié)構(gòu)可控性差、復(fù)合層易剝離等缺點(diǎn),進(jìn)而造成納濾膜結(jié)構(gòu)和性能穩(wěn)定性差等問題。聚丙烯腈的玻璃態(tài)轉(zhuǎn)變溫度較高,具有良好的熱穩(wěn)定性、耐溶劑性、化學(xué)穩(wěn)定性和較好的親水性,所以常用來制備反滲透的基膜,超濾膜等,但聚丙烯腈結(jié)構(gòu)單元中有強(qiáng)極性的氰基,使分子鏈旋轉(zhuǎn)困難,造成聚丙烯腈膜材料的機(jī)械強(qiáng)度和韌性差,因而限制了其廣泛應(yīng)用。無機(jī)/高分子復(fù)合膜兼具聚合物優(yōu)異的加工性能和無機(jī)填料的獨(dú)特性能,是今后分離膜的發(fā)展方向。作為一種新型優(yōu)質(zhì)聚合物改性材料,氧化石墨烯具有良好的親水性、較高的比表面能以及機(jī)械性能。本文采用熱致相分離法和小分子層層自組裝法制備了結(jié)構(gòu)穩(wěn)定、力學(xué)性能和分離效果良好的抗污染納濾膜。首先采用熱致相分離法制備氧化石墨烯/聚丙烯腈復(fù)合膜,所制備的復(fù)合膜表現(xiàn)出優(yōu)異的力學(xué)強(qiáng)度、較高的滲透性能、高染料截留率、低鹽截留率以及良好的抗污性能,適用于印染廢水的處理和染料的純化處理。研究發(fā)現(xiàn)聚丙烯腈膜的膜孔結(jié)構(gòu)、相分離溫度、孔隙率、滲透和機(jī)械性能等受添加劑種類、聚合物濃度、冷卻浴等因素的影響,結(jié)果表明采用與聚丙烯腈相容性較差,極性分?jǐn)?shù)和分子量較小的甘油作為添加劑所制備的膜性能較好。增加聚合物濃度使得膜結(jié)構(gòu)變致密,體系的相分離溫度升高,膜的孔隙率和純水通量下降,拉伸強(qiáng)度和染料的截留率增大。降低冷卻速率使得分離膜結(jié)構(gòu)變疏松,孔隙率增大且水通量上升。采用溶劑交換法將制備好的氧化石墨烯均勻分散在膜中制備得到氧化石墨烯/聚丙烯腈共混膜,發(fā)現(xiàn)氧化石墨烯的加入使得聚合物晶粒尺寸增大,當(dāng)氧化石墨烯的添加量0.2wt%,共混膜的水通量比原膜提高了83%,具有高染料截留和低鹽截留性能。由于氧化石墨烯的親水性和增強(qiáng)效果,分離膜的通量恢復(fù)率和拉伸強(qiáng)度分別提高到84%和12.46mpa。采用胺化改性的氧化石墨烯/聚丙烯腈共混膜作為基膜,再用界面聚合和小分子層層自組裝法制備復(fù)合納濾膜,胺化改性膜表面的胺基能提高基膜與活性層的結(jié)合力。與界面聚合法相比,采用小分子層層自組裝法制備的納濾膜結(jié)構(gòu)更穩(wěn)定,膜的表面電荷可調(diào)控;通過改變反應(yīng)單體種類發(fā)現(xiàn)采用剛性結(jié)構(gòu)的間苯二胺制備的膜分離性能比柔性結(jié)構(gòu)的二乙烯三胺更優(yōu),隨著自組裝層數(shù)增加,分離膜水通量下降而截留率增加;通過在自組裝過程中引入氧化石墨烯能夠提高納濾膜的截留性能,氧化石墨烯溶液的最佳濃度為1mg/ml,調(diào)節(jié)單體濃度、反應(yīng)時(shí)間和熱處理溫度探索復(fù)合納濾膜的最佳制備條件,測(cè)試發(fā)現(xiàn)復(fù)合膜性能發(fā)現(xiàn)小分子層層自組裝復(fù)合膜具有較高的無機(jī)鹽截留率和抗污性能,對(duì)硫酸鈉的截留率為74.7%,膜表面負(fù)載的氧化石墨烯優(yōu)異的親水性使分離膜的通量恢復(fù)率達(dá)到91.3%。
[Abstract]:Membrane separation technology has the advantages of efficient separation, concentration, purification and purification. In recent years, with the increasing demand of water resources and water standards, the pressure of the sewage treatment is increasing, the research of nanofiltration membrane has been greatly promoted. Between the separation performance of nanofiltration membrane between ultrafiltration and reverse osmosis membrane, mainly used for separation the molecular weight of small molecules between the 200-2000, is widely used for water softening, printing and dyeing wastewater treatment, food and pharmaceutical industry and other fields. The traditional non solvent preparation of nanofiltration membrane by induced phase separation method and composite method is easy to cause the membrane structure of low strength, poor controllability, composite layer easy peeling defects then the problems caused by nanofiltration membrane structure and performance stability. The glass transition temperature of polyacrylonitrile high, has good thermal stability, solvent resistance, chemical stability and good hydrophilic, so often Used for preparation of reverse osmosis membrane, ultrafiltration membrane, but the structure of polyacrylonitrile unit has strong polar cyano, the molecular chain rotation caused by the material difficulties, polyacrylonitrile membrane mechanical strength and toughness is poor, which limits its wide application. With the unique properties of polymers with excellent mechanical properties and inorganic fillers inorganic / polymer composite membrane, membrane separation is the future direction of development. As a new high polymer modified materials, graphene oxide has good hydrophilicity, high surface energy and mechanical properties. This method and small molecular self-assembly were prepared by thermally induced phase separation structure stability, mechanical properties and good separation effect the anti pollution nanofiltration membrane. Firstly using heat to prepare graphene oxide / PAN composite membrane induced phase separation, the prepared composite films exhibit excellent mechanical strength, high permeability, high The dye retention rate, low salt rejection and anti fouling performance good, purification and treatment of dyes for dyeing wastewater. The study found that the porous structure of polyacrylonitrile membrane, phase separation temperature, porosity, permeability and mechanical properties by additives, polymer concentration, cooling bath and other factors, the results show that the use of poor compatibility with polyacrylonitrile, polar fraction and low molecular weight glycerol as additive membranes were prepared. The performance is better with increasing the polymer concentration makes the membrane structure compact, phase separation temperature system, decrease the porosity and the pure water flux, retention rate of tensile strength increases and dyes. Lower cooling rate makes the separation membrane the loose structure, porosity and water flux increase. The solvent exchange method for graphene oxide prepared uniformly prepared graphene oxide / Polypropylene Membranes Nitrile blend film, found that adding graphene oxide makes the polymer grain size increases, when the graphene oxide 0.2wt% was added, the water flux was 83% higher than the original film, with high dye retention and low salt rejection performance. Due to the hydrophilicity of graphene oxide and enhance the effect of graphene oxide / separation the membrane flux recovery rate and tensile strength were increased to 84% and 12.46mpa. by amination of modified polyacrylonitrile blend membrane as a basement membrane, and interfacial polymerization and small molecular self-assembly preparation of composite nanofiltration membrane, amino amine modified membrane surface can increase the adhesion between the basement membrane and the active layer. Compared with the method of interfacial polymerization using small molecule layer self nanofiltration membrane structure assembly prepared more stable. The surface charge of the membrane can be controlled by changing the reaction; the monomer species found by membrane separation performance between the two benzene amine preparation rigid structure than The flexible structure two three ethylene amine is better, with self assembled layers increased, membrane water flux decreased and the retention rate increased; through the self-assembly process into graphene oxide can improve the retention performance of nanofiltration membrane, the optimal concentration of graphene oxide solution is 1mg/ml, adjusting the monomer concentration, reaction time and preparation conditions the heat treatment temperature on composite nanofiltration membrane was optimized, the test found that the properties of the composite film found inorganic small molecular self-assembly composite membrane has high retention rate and anti fouling performance of sodium sulfate removal rate is 74.7% and the surface negative hydrophilic graphene oxide carrier excellent separating membrane flux recovery rate reached 91.3%.

【學(xué)位授予單位】：東華大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TQ051.893

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