本文選題：接枝改性　切入點：共混改性　出處：《天津工業(yè)大學》2017年博士論文　論文類型：學位論文

【摘要】：硼作為一種重要的化學元素,廣泛應(yīng)用于現(xiàn)代工業(yè)領(lǐng)域中。適量的硼元素能夠促進動植物體的生長發(fā)育,而硼含量過高,會導致動植物體出現(xiàn)中毒現(xiàn)象。世界衛(wèi)生組織(WHO)規(guī)定,飲用水中硼濃度不超過2.4 mg/L,灌溉水中硼濃度不超過1 mg/L。而海水中硼的平均濃度為5mg/L,遠超WHO所規(guī)定,因此海水除硼在海水淡化過程中非常重要。目前,海水除硼技術(shù)發(fā)展迅速,但很多方法除硼效果并不理想。本課題組的工作表明,螯合膜分離法是一種非常高效的去除水溶液中硼酸的方法。這種方法利用膜表面上鄰位羥基聚合物與硼酸發(fā)生絡(luò)合反應(yīng),達到過濾過程中除硼的目的,操作簡單,便于推廣。本文通過表面接枝和共混等方法制備出三種螯合膜材料,用全反射紅外光譜(FT-IR)、X-射線光電子能譜(XPS)、水接觸角(WCA)、場發(fā)射掃描電鏡(FESEM)、原子力顯微鏡(AFM)以及BET(Brunauer-Emmett-Teller)等方法對螯合膜的結(jié)構(gòu)與性能進行表征,考察了螯合膜在不同硼酸溶液初始濃度、pH值和離子強度等條件下對硼酸的吸附性能,并研究了螯合膜的吸附熱力學和吸附動力學以及循環(huán)再生性能。首先,通過將聚丙烯腈(PAN)膜上的氰基水解和酰胺化作用,在PAN膜表面接枝了具有超支化聚乙烯亞胺(HPEI),再通過氨基與環(huán)氧丙烷的開環(huán)反應(yīng),制備出一系列具有表面接枝超支化多元醇的PAN改性膜材料PAN-g-PG。PAN-g-PG膜具有很高的吸附容量和很快的吸附速率。研究發(fā)現(xiàn),PAN膜表面接枝PG后展現(xiàn)出超親水性能,且表面粗糙度增加。吸附熱力學和吸附動力學分析表明,螯合膜的硼吸附符合Langmuir等溫吸附模型和偽一級動力學模型。當硼酸初始濃度為100mg/L時,螯合膜的最大吸附量為3.2mmol/g,達到吸附平衡的時間僅為4 min。通過在鹽酸中處理15min,PAN-g-PG膜吸附再生率為100%。螯合膜經(jīng)過循環(huán)10次后,再生率仍接近100%,表現(xiàn)出良好的循環(huán)再生性能。其次,為了進一步增加螯合膜的比表面積,增大螯合膜對硼酸的吸附容量,利用靜電紡絲技術(shù)制備聚酰胺酸(PAA)納米纖維膜,并在纖維膜表面通過酰胺化反應(yīng)和環(huán)氧開環(huán)反應(yīng),成功的引入多元醇結(jié)構(gòu)。結(jié)果表明,PAA鑄膜液固含量為15%時,PAA納米纖維膜具有均一的形貌和相對窄的纖維直徑分布。XPS和FT-IR表征證明,HPEI和環(huán)氧丙醇成功的接枝在膜表面上,兩步反應(yīng)的接枝率隨著與HPEI接枝反應(yīng)時間的增加而增加。PAA-g-PG24納米纖維膜在270 mg/L、pH=9的硼酸溶液中出現(xiàn)最大吸附量,為5.68mmol/g,這是目前文獻中報道的最高吸附量。在5mg/L初始硼酸濃度下,PAA-g-PG24納米纖維膜對硼酸的吸附量為0.82mmol/g,且吸附平衡時間為15min。PAA-g-PG24納米纖維膜吸附過程符合Langmuir熱力學吸附模型和偽一級動力學模型。經(jīng)過10次循環(huán)后,PAA-g-PG24納米纖維膜的RE值仍保持在93.9%,表現(xiàn)出很好的循環(huán)利用性能。最后,為了簡化制膜過程,通過相轉(zhuǎn)化法,將具有脫硼功能的特異性吸附樹脂(BSR)與聚砜(PSF)共混,用非溶劑相轉(zhuǎn)化法制備了 PSF/BSR混合基質(zhì)膜�；旌匣|(zhì)膜比聚合物樹脂具有更快的吸附速率,這使膜對較低濃度的硼酸溶液更具吸附優(yōu)勢。當處理10mL濃度為5mg/L硼酸溶液時,PSF/BSR4共混膜通量為25 L/m2·h,硼去除率為97.6%,循環(huán)10次后,恢復率可保持在95.9%。
[Abstract]:Boron is an important chemical element, widely used in modern industrial fields. The amount of boron can promote the growth of animals and plants, and the boron content is too high, will lead to animal and plant poisoning occurs. The WHO (WHO), boron in drinking water was less than 2.4 mg/L, the irrigation water concentration of boron more than 1 mg/L. and the average concentration of boron in seawater was 5mg/L, far exceeding the required WHO, therefore seawater boron removal is very important in the desalination process. At present, seawater boron removal technology is developing rapidly, but many methods of boron removal effect is not ideal. This work shows that the chelating membrane separation method is a very efficient removal of boric acid in aqueous solution. This method uses the membrane surface of ortho hydroxyl polymer with boric acid complexation reaction to filtration process of boron removal, simple operation and easy popularization. This paper through the table Surface grafting and blending method to prepare three kinds of chelating membrane materials by total reflection infrared spectroscopy (FT-IR), X- ray photoelectron spectroscopy (XPS), water contact angle (WCA), field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM) and BET (Brunauer-Emmett-Teller) of structure and characterization the methods of chelating membrane, were investigated at different initial concentrations of boric acid chelating membrane solution, the adsorption properties for boric acid pH value and ionic strength conditions, and studied the chelating membrane adsorption thermodynamics and adsorption kinetics and recycling performance. First, by using polyacrylonitrile (PAN) membrane on the hydrolysis of cyano group and acyl amination, grafted on the surface of PAN film with hyperbranched polyethylenimine (HPEI), and then through the ring opening reaction of amino and epoxy propane, preparation of a series of surface grafted with hyperbranched polyol PAN modified PAN-g-PG.PAN-g-PG membrane with a membrane material High adsorption capacity and fast adsorption rate. The study found that grafted on the surface of PAN film PG exhibit hydrophilic properties, and the surface roughness increases. The adsorption thermodynamics and kinetics analysis showed that the adsorption of boron chelate membrane accords with Langmuir isotherm model and pseudo first order kinetic model. When the initial concentration of boric acid was 100mg/L. The maximum adsorption capacity of the chelating membrane is 3.2mmol/g, the adsorption equilibrium time is only 4 of min. treated by 15min in hydrochloric acid, PAN-g-PG membrane adsorption regeneration rate of 100%. chelating membrane after after 10 cycles, the regeneration rate is close to 100%, showing good performance of regeneration cycle. Secondly, in order to further increase the chelating membrane surface the area, the adsorption capacity increased to boric acid chelating membrane, preparation of polyamic acid by electrospinning (PAA) nano fiber membrane, and the membrane surface by amidation reaction and epoxy ring opening reaction into The introduction of the polyols power. The results show that the PAA casting solution when solid content is 15%, and the relatively narrow fiber morphology of PAA nano fiber film with uniform diameter distribution of.XPS and FT-IR indicated that HPEI and glycidol successfully grafted onto the membrane surface, increase the grafting reaction of the two step rate with HPEI the grafting reaction time and increase of.PAA-g-PG24 nano fiber membrane at 270 mg/L, the maximum adsorption capacity, appear boric acid solution pH=9 for 5.68mmol/g, which is the highest adsorption capacity reported in the current literature. In 5mg/L the initial concentration of boric acid, the adsorption amount of PAA-g-PG24 nano fiber membrane of boric acid is 0.82mmol/g, and the time of adsorption equilibrium thermodynamics with Langmuir adsorption model and pseudo first order kinetic model for 15min.PAA-g-PG24 nano fiber membrane adsorption process. After 10 cycles, PAA-g-PG24 nano fiber membrane remained at RE 93.9%, showed good evidence The use of ring performance. Finally, in order to simplify the process of the film was prepared by phase inversion method, the specific function of the removal of boron adsorption resin (BSR) and polysulfone (PSF) blends, PSF/BSR mixed matrix membranes were prepared by non solvent phase. Mixed matrix membrane has faster adsorption rate than the polymer resin, which makes the the membrane of boric acid solution with low concentration the more adsorption advantage. When processing the 10mL concentration of 5mg/L boric acid solution, PSF/BSR4 blend membrane flux is 25 L/m2 - H, the boron removal rate was 97.6%, after 10 cycles, the recovery rate can be maintained at 95.9%.

【學位授予單位】：天津工業(yè)大學
【學位級別】：博士
【學位授予年份】：2017
【分類號】：TQ051.893

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