本文選題：復(fù)合納濾膜　切入點(diǎn)：羧甲基殼聚糖　出處：《湘潭大學(xué)》2017年碩士論文

【摘要】：納濾(NF)膜的截留分子量(MWCO)介于200-1000 Da,它可以有選擇性地高效截留水體中的無(wú)機(jī)鹽離子、有機(jī)小分子、細(xì)菌和病菌等。目前主流商品化的NF膜是荷電的復(fù)合NF膜,按所帶電性可分為荷正電、荷負(fù)電及兩性復(fù)合NF膜。羧甲基殼聚糖(CMCS)是殼聚糖的一種水溶性兩性衍生物,其分子結(jié)構(gòu)上含有大量的COO-。磷酸酯化聚乙烯醇(PPVA)是聚乙烯醇的磷酸酯化后的產(chǎn)物。其分子結(jié)構(gòu)上含有大量的PO3-4。在本研究中以CMCS和PPVA作為復(fù)合NF膜的表面活性材料,以乙二醇二縮水甘油醚(EGDE)作為交聯(lián)劑,30000 Da聚砜超濾膜(PSF UF)為基膜,利用涂覆交聯(lián)的方法,在一定的制備工藝下制備了CMCS/PSF和PPVA/PSF兩種新型NF膜。利用衰減全反射紅外光譜(ATR-IR)、環(huán)境掃描電子顯微鏡(ESEM)、靜態(tài)接觸角測(cè)量?jī)x等儀器對(duì)其結(jié)構(gòu)、形貌和膜表面的親水性進(jìn)行了表征,并研究了其最佳的制備條件及各種外界操作因素對(duì)最佳條件制備的膜的分離性能的影響。以5 mmol/L的Na_2SO_4作為料液。研究發(fā)現(xiàn),CMCS/PSF系列復(fù)合NF膜最佳的制備工藝條件為:鑄膜液的濃度為2 wt%,交聯(lián)劑的濃度為5 vol%,交聯(lián)反應(yīng)的溫度為70℃,交聯(lián)反應(yīng)的時(shí)間為25 min。最佳制備條件下,隨著壓力的升高,CMCS/PSF復(fù)合NF膜的截留率先升高,后降低,通量則幾乎呈線性遞增。隨著料液流量的增大,CMCS/PSF復(fù)合NF膜的截留率和通量均先降低后升高。CMCS/PSF復(fù)合NF膜對(duì)不同鹽截留率按從大到小的順序?yàn)?Na_2SO_4、NaCl、KCl、MgSO4、MgCl2,且對(duì)Na_2SO_4和NaCl的截留率和通量均會(huì)隨著鹽濃度的升高而降低。隨著甘油質(zhì)量分?jǐn)?shù)的提高,CMCS/PSF復(fù)合NF膜的截留率先下降后升高,通量表現(xiàn)和截留率相反,先升高后下降。研究發(fā)現(xiàn),PPVA/PSF系列復(fù)合NF膜的最佳制備條件為:鑄膜液濃度為1wt%,交聯(lián)劑濃度為20 vol%,交聯(lián)反應(yīng)溫度為75℃,交聯(lián)反應(yīng)時(shí)間為30 min。隨著壓力的升高,最佳制備條件下制備的PPVA/PSF復(fù)合NF膜的截留率先升高,后降低,通量則幾乎呈線性遞增。隨著料液通量的增大,最佳條件下制備的PPVA/PSF復(fù)合NF膜的截留率和通量均先降低后升高。PPVA/PSF復(fù)合NF膜對(duì)不同鹽截留率從大到小的順序?yàn)?Na_2SO_4、NaCl、KCl、MgSO4、MgCl2,且對(duì)Na_2SO_4和NaCl的截留率和通量均會(huì)隨著鹽濃度的升高而降低。隨著甘油質(zhì)量分?jǐn)?shù)的提高,PPVA/PSF復(fù)合NF膜的截留率呈線性下降,通量線性增長(zhǎng)。在外界操作壓力為0.4 MPa,料液通量為0.9 L/min和室溫的條件下PPVA/PSF復(fù)合NF膜對(duì)仿真海水的截留率能達(dá)到75%以上,通量達(dá)到7.6kg·m-2·h-1以上。表明在分離海水的過(guò)程中可以將海水看作為一種“綜合性的無(wú)機(jī)鹽”。PPVA/PSF復(fù)合NF膜對(duì)三種典型的有機(jī)染料也具有較好的分離性能。其中對(duì)3 mg/L的堿性品紅的截留率和通量分別為93.4%和13.2 kg·m~(-2)·h~(-1)。
[Abstract]:Nanofiltration (NFN) membrane has a molecular weight of MWCO between 200-1000 Da.It can selectively and efficiently intercept inorganic salt ions, organic small molecules, bacteria and bacteria in water.At present, the main commercial NF films are charged composite NF films, which can be divided into positive charged, negative charged and amphoteric composite NF films according to their electrical properties.Carboxymethyl chitosan (CMCS) is a water-soluble amphoteric derivative of chitosan.Phosphate polyvinyl alcohol (PPVA) is the product of polyvinyl alcohol phosphate.Its molecular structure contains a large amount of PO3-4.In this study, CMCS and PPVA were used as the surface active materials of NF composite membrane, and ethylene glycol diglycidyl ether (EGDE) as crosslinking agent, 30 000 Da polysulfone ultrafiltration membrane was used as the base membrane, and the method of coating crosslinking was used.Two new NF membranes, CMCS/PSF and PPVA/PSF, were prepared under certain preparation conditions.The structure, morphology and hydrophilicity of the films were characterized by means of attenuated total reflectance infrared spectroscopy (ATR-IRN), environmental scanning electron microscopy (ESM) and static contact angle measuring instrument.The optimum preparation conditions and the effects of various external operating factors on the separation properties of the membranes prepared under the optimum conditions were studied.5 mmol/L Na_2SO_4 was used as feed liquid.It was found that the optimum preparation conditions of CMCS / PSF composite NF membrane were as follows: the concentration of casting solution was 2 wts, the concentration of crosslinking agent was 5 vols, the temperature of crosslinking reaction was 70 鈩，

本文編號(hào)：1728647