發(fā)布時間：2018-07-03 09:20

  本文選題：靜電紡絲 + 醋酸纖維素��； 參考：《五邑大學》2014年碩士論文

【摘要】：靜電紡絲作為一項制備納米纖維材料的新技術,其所制備的納米纖維膜具有纖維直徑小、比表面積大、孔隙率高等特點,從而使靜電紡納米纖維膜在水體有害物質過濾及吸附方面有著極大的應用潛力。 本文通過以環(huán)保型材料醋酸纖維素(CA)為主要組分,聚丙烯腈(PAN)為添加組分,利用靜電紡絲法制備了CA/PAN復合納米纖維膜。在此基礎上,通過對復合膜后期的改性處理制備了功能化CA復合納米纖維膜,進一步研究了其對水溶液中六價鉻離子(Cr6+)的吸附分離性能,本文主要進行了以下幾個方面的工作：首先在探討了CA. PAN混合溶液特性的基礎上,利用多噴頭靜電紡絲制備了CA/PAN復合纖維膜,通過掃描電鏡(SEM)對纖維形貌表征發(fā)現(xiàn),在以強極性溶劑二甲基亞砜(DMSO)為溶劑時,PAN的混入提高了共混溶液的可紡性。紅外圖譜(FT-IR)分析表明,在以CA為主要組分的復合纖維中,CA、PAN存在一定程度的分子級相容,為部分相容體系。其次,通過對不同比例的纖維膜力學性能及熱性能分析發(fā)現(xiàn),PAN含量的增加有助于提高復合膜的斷裂強力和熱穩(wěn)定性,且CA/PAN復合比例在7/3時斷裂強力達到最大值294.6cN,斷裂伸長率9.33%,但再繼續(xù)增大PAN的比例復合膜的力學性能將下降,從而確定了最佳的CA/PAN復合比例為7/3。在此基礎上,進一步探討了各紡絲參數(shù)對纖維直徑大小及纖維膜比表面積的影響,并通過對紡絲工藝條件的優(yōu)化,獲得纖維直徑分布均勻且大小在200nm左右的復合納米纖維膜。最后,利用鹽酸羥胺溶液對CA復合膜進一步改性處理,FT-IR圖譜分析表明,本文成功制備了含有偕胺肟基團的CA復合納米纖維膜,并通過對復合膜中腈基轉化率的探討及改性后復合膜力學性能的表征,獲得了最佳的改性條件。 對Cr6+吸附數(shù)據(jù)表明,CA復合膜的改性處理顯著提高了其對重金屬離子的吸附性能,且對Cr6+吸附過程符合朗格繆爾(Langmuir)單分子層等溫吸附模型,吸附過程為定向吸附且存在飽和吸附值,各溫度點的最大理論吸附量分別為74.29mg/g(30℃)、77.10mg/g (40℃),79.24mg/g (50℃),且復合膜對Cr6+吸附過程符合準二階動力學吸附反應。吸附熱力學研究發(fā)現(xiàn),纖維膜對Cr6+的吸附為吸熱過程,且吸附過程可自發(fā)進行,吸附過程除存在物理和化學吸附反應之外,纖維膜與Cr6+之間可能還發(fā)生了離子交換反應。
[Abstract]:Electrospinning is a new technology for preparing nanofiber materials. The nanofiber membrane has the characteristics of small fiber diameter, large specific surface area, high porosity and so on. Therefore, the electrospun nanofiber membrane has great application potential in the filtration and adsorption of harmful substances in water body. In this paper, CA / pan composite nanofiber membranes were prepared by electrospinning with cellulose acetate (CA) as the main component and polyacrylonitrile (pan) as the additive component. On this basis, the functionalized CA nanofiber membrane was prepared by the late modification of the composite membrane, and the adsorption and separation properties of Cr 6 in aqueous solution were further studied. The main work of this paper is as follows: firstly, CAA is discussed. On the basis of the properties of pan mixed solution, CA / pan composite fiber membrane was prepared by multi-nozzle electrostatic spinning. The morphology of the fiber was characterized by scanning electron microscopy (SEM). When dimethyl sulfoxide (DMSO) was used as solvent, the spinnability of the blend solution was improved. The infrared spectra (FT-IR) analysis showed that there was a certain degree of molecular compatibility of CAPAN in the composite fibers with CA as the main component, and it was a partial compatibility system. Secondly, through the analysis of the mechanical and thermal properties of fiber membrane with different proportion, it is found that the increase of pan content can improve the fracture strength and thermal stability of the composite membrane. When the ratio of CA- / pan composite is 7 / 3, the maximum breaking strength is 294.6 CN, the elongation at break is 9.33, but the mechanical properties of the composite membrane with increasing the ratio of pan will decrease, and the optimum ratio of CA-PAN is 7 / 3. On this basis, the effects of spinning parameters on fiber diameter and fiber membrane specific surface area were further discussed. By optimizing the spinning process conditions, the composite nanofiber membrane with uniform fiber diameter distribution and size about 200nm was obtained. Finally, the FT-IR spectra of CA composite membrane modified by hydroxylamine hydrochloride solution showed that the CA composite nanofiber membrane containing amidoxime group was successfully prepared. The optimum modification conditions were obtained by discussing the conversion of nitrile group in the composite membrane and characterizing the mechanical properties of the modified composite membrane. The adsorption data of Cr _ 6 show that the modification of the composite membrane can significantly improve the adsorption performance of heavy metal ions, and the adsorption process of Cr _ 6 is in accordance with Langmuir monolayer isotherm adsorption model. The adsorption process is orientated and saturated, and the maximum theoretical adsorption capacity at each temperature is 77.10 mg / g (40 鈩，

本文編號：2093165