本文選題：納濾膜 + 仿生粘合　； 參考：《哈爾濱工業(yè)大學(xué)》2017年碩士論文

【摘要】：水資源短缺已經(jīng)成為當(dāng)今社會(huì)面臨的嚴(yán)峻問題,而染料廢水的排放也一直威脅著全球性的水安全。傳統(tǒng)的用于處理染料廢液的方法包括絮凝、吸收和化學(xué)降解等,但是這些過程中往往會(huì)帶來二次污染問題。相比而言,發(fā)展于二十世紀(jì)六十年代的膜分離技術(shù)節(jié)能、高效、環(huán)保、操作簡單。納濾膜作為一種壓力驅(qū)動(dòng)型分離膜,截留分子量在200~1000 Da范圍內(nèi),可以在廢水處理、開發(fā)水的再利用方面發(fā)揮重要作用。用簡單的工藝制備出性能優(yōu)異的納濾膜是科學(xué)家面臨的一大挑戰(zhàn)。單寧酸(TA)作為一種天然的植物多酚,具備良好的生物粘附性和豐富的物理化學(xué)性能。本文首先利用TA與金屬離子的螯合作用,以TA作為有機(jī)配體,分別選用過渡金屬離子Ag+、Co~(2+)、Ni~(2+)、Cu~(2+)、Fe3+作為無機(jī)交聯(lián)劑,在超濾膜表面形成穩(wěn)定的交聯(lián)網(wǎng)絡(luò)結(jié)構(gòu)。經(jīng)過初步篩選發(fā)現(xiàn),當(dāng)固定二者的比例為1:1時(shí),所得到的TA/Co~(2+)、TA/Ni~(2+)復(fù)合納濾膜的滲透通量分別為42.5 L m~(-2) h~(-1) bar~(-1)和45.6 L m~(-2) h~(-1)bar~(-1),要比其他的高出3~4倍。為了進(jìn)一步研究金屬離子濃度對(duì)所形成涂層結(jié)構(gòu)的影響,制備了不同比例下的TA/Ni~(2+)涂覆復(fù)合納濾膜。改變TA與金屬離子Ni~(2+)的配比從2:1、1:1、1:2至1:3,水通量呈現(xiàn)出先增加后降低的趨勢(shì)。當(dāng)調(diào)節(jié)TA與Ni~(2+)的比例為1:2時(shí),水通量達(dá)到最高為56.1 L m~(-2) h~(-1) bar~(-1),此時(shí)納濾膜對(duì)有機(jī)染料孟加拉玫瑰紅的截留率是95.3%。結(jié)合TA分子結(jié)構(gòu)中含有的大量酚羥基基團(tuán),在水溶液中與聚乙烯亞胺(PEI)之間存在強(qiáng)烈的氫鍵作用和靜電作用,通過一步組裝在基底表面形成涂層結(jié)構(gòu)。這部分實(shí)驗(yàn)主要考察了TA和PEI的濃度,以及組裝層數(shù)對(duì)于納濾膜分離性能的影響。研究發(fā)現(xiàn),該法制備的復(fù)合納濾膜的表面帶有部分正電荷,對(duì)正電性染料的截留更加有效。當(dāng)PEI的濃度固定時(shí),隨著TA濃度的增加,在膜的表面形成的選擇層結(jié)構(gòu)更加致密,滲透通量隨著TA濃度的增加而降低,對(duì)有機(jī)染料甲基藍(lán)的截留率從85.5%到99.8%,而對(duì)維多利亞藍(lán)B的截留率則是從88.2%提高到了100%。與以TA濃度作為變量不同的是,改變外層PEI的濃度,更多地影響到的是膜表面的親水性,水接觸角從53.1o下降到18.6o,水的滲透通量增加。另外,通過反復(fù)組裝還可以對(duì)該納濾膜的性能實(shí)現(xiàn)進(jìn)一步調(diào)節(jié)。
[Abstract]:The shortage of water resources has become a serious problem in our society, and the discharge of dye wastewater has been threatening the global water security. The traditional methods used to treat dye waste liquid include flocculation, absorption and chemical degradation, but these processes often bring secondary pollution problems. In contrast, the membrane separation technology developed in the 1960's is energy efficient, environmentally friendly and easy to operate. Nanofiltration membrane, as a kind of pressure driven separation membrane, with a molecular weight of 200 ~ 1000Da, can play an important role in wastewater treatment and water reuse. The preparation of nanofiltration membranes with excellent performance by simple process is a great challenge for scientists. As a kind of natural plant polyphenols, TAA has good bioadhesion and abundant physical and chemical properties. In this paper, a stable cross-linking network structure was formed on the surface of ultrafiltration membrane by the chelation of TA with metal ions, using TA as organic ligand, and the transition metal ion Ag / CoCoC _ (2) O _ (2) Ni ~ (2) C _ (2) O _ (2) C _ (2) O _ (2) Fe _ (3) as inorganic crosslinking agent. After preliminary screening, it was found that the permeable fluxes of the composite nanofiltration membranes were 42.5 L ~ (m ~ (-1) and 45.6 L ~ (-1) ~ (-1) bar-1 ~ (-1) bar-1m ~ (-1), respectively, when the fixed ratio of them was 1:1, which was 3 ~ 4 times higher than that of the other membranes, and the results showed that the permeation flux of the composite nanofiltration membranes was 42.5 L ~ (-1) and 45.6 L ~ (-1) ~ (-1) bar-1 ~ (-1) ~ (-1), which was 3 ~ 4 times higher than that of the others. In order to further study the effect of metal ion concentration on the structure of the coating, the composite nanofiltration membrane (TA/Ni~(2) coated with different ratio was prepared. When the ratio of TA to Ni~(2) was changed from 2: 1 to 1: 1: 2 to 1: 3, the water flux increased first and then decreased. When the ratio of TA to Ni~(2 was adjusted to 1:2, the water flux reached the maximum of 56.1 L / m ~ (-2) 路h ~ (-1) ~ (-1) ~ (-1) ~ (-1) ~ (-1) ~ (-1), and the rejection rate of the nanofiltration membrane to the organic dye, Bengal rose red, was 95.3%. In combination with a large number of phenolic hydroxyl groups in TA molecular structure, there is a strong hydrogen bond and electrostatic interaction between the hydroxyl group in aqueous solution and polyethylene imide (PEI). The coating structure is formed on the substrate surface by one-step assembly. The effects of TA and PEI concentrations and the number of assembly layers on the separation performance of nanofiltration membranes were investigated. It is found that the surface of the composite nanofiltration membrane prepared by this method has partial positive charge, which is more effective for the retention of positive dyes. When the concentration of PEI was fixed, with the increase of TA concentration, the selective layer formed on the surface of the membrane became denser, and the permeation flux decreased with the increase of TA concentration. The rejection rate of organic dye methyl blue increased from 85.5% to 99.8%, while that of Victoria blue B increased from 88.2% to 100%. Different from TA concentration, the hydrophilicity of membrane surface is more affected by changing the concentration of outer PEI, the water contact angle decreases from 53.1 o to 18.6 o. the permeation flux of water increases. In addition, the performance of the nanofiltration membrane can be further adjusted by repeated assembly.
【學(xué)位授予單位】：哈爾濱工業(yè)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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相關(guān)期刊論文 前1條

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本文編號(hào)：1806645