【摘要】：本文通過氧化石墨烯（GO）與乙二胺（EDA）發(fā)生脫水縮合反應生成氨基功能化改性的氧化石墨烯（GO-NH2），再利用多巴胺的自聚合性和化學特性，將功能化的GO與涂覆在超濾膜表面的聚合多巴胺形成共價鍵，，從而將功能化的GO接枝到聚偏氟乙烯(PVDF)超濾膜表面，形成親水性強、導電性強的膜表面。本文的研究重點為氨基功能化氧化石墨烯的合成方法和PVDF超濾膜接枝功能化GO后的膜面表征與抗污染性能，利用GO的片狀結(jié)構(gòu)在超濾膜表面形成更致密的石墨烯膜分離層，從而達到更精密的過濾效果。 通過脫水縮合反應形成功能化氧化石墨烯，利用傅里葉紅外光譜（FTIR）、熱重分析（TGA）和環(huán)境掃描電鏡（ESEM）對產(chǎn)物進行檢測，結(jié)果顯示，氨基成功接枝到氧化石墨烯片層結(jié)構(gòu)上。利用膜表面的聚合多巴胺將改性氧化石墨烯接枝到PVDF超濾膜表面，采用ESEM和FTIR分別對改性前后膜表面結(jié)構(gòu)形態(tài)和化學組成進行觀察，利用不同接枝濃度和接枝時間的超濾膜表面的接觸角及其變化來表征改性對膜親水性和潤濕性的影響，并將改性膜過濾機油乳化液、牛白蛋白（BSA）和海藻酸鈉（SA）溶液三種模擬廢水體系，研究改性對膜抗污染性能和截留能力的影響，最后進行改性膜的酸堿穩(wěn)定性測試。 結(jié)果顯示，接枝功能化GO使膜孔徑縮小和孔隙率降低，但使其親水性和潤濕性增強。膜表面的親水性和潤濕性隨接枝濃度的增大和接枝時間的增長而增強，而純水通量隨接枝濃度的增大和接枝時間的增長呈現(xiàn)先上升后下降的趨勢。實驗采用的PVDF超濾膜的平均接觸角為77°，經(jīng)接枝改性后接觸角平均值減小為61°，PVDF超濾膜的純水通量由206.8L/(m2.h)減小為120.4(m2.h)。最佳的GO-NH2接枝濃度為2mg/mL，接枝時間為60min。 通過利用機油乳化液、BSA和SA三種溶液模擬廢水體系對改性膜進行過濾實驗研究了改性膜的抗污染性能，結(jié)果顯示，改性使得膜的抗污染能力有所提高；通過對改性膜進行酸堿浸泡，利用膜的純水通量和膜表面接觸角進行了膜的穩(wěn)定性測試，結(jié)果顯示，改性膜具有良好的耐酸性，但耐堿性相對較弱些。最后，通過利用55℃、1%的表面活性劑水溶液對機油乳化液污染膜進行清洗以及55℃、1%NaOH溶液對BSA溶液和SA溶液污染膜進行清洗發(fā)現(xiàn)，改性膜的恢復率都在60%以上。
[Abstract]:In this paper, graphene oxide (GO-NH2) was synthesized by dehydration and condensation of graphene oxide (GO) with ethylenediamine (EDA) to form amino-functionalized graphene oxide (GO-NH2), and the self-polymerization and chemical properties of dopamine were used. The functionalized go was covalently bonded with the polymerized dopamine coated on the surface of the ultrafiltration membrane, and the functionalized go was grafted onto the surface of the polyvinylidene fluoride (PVDF) ultrafiltration membrane to form a surface with strong hydrophilicity and conductivity. In this paper, the synthesis method of amino-functionalized graphene oxide and the surface characterization and antifouling performance of PVDF ultrafiltration membrane grafted with go were emphasized. A denser graphene membrane separation layer was formed on the surface of ultrafiltration membrane by using the sheet structure of go. Thus, a more precise filtration effect is achieved. The functionalized graphene oxide was formed by dehydration and condensation reaction. The products were detected by Fourier transform infrared spectroscopy (FTIR),) thermogravimetric analysis (TGA) and environmental scanning electron microscopy (ESEM). The results showed that the amino groups were grafted onto the graphene oxide lamellar structure successfully. The modified graphene oxide was grafted onto the surface of PVDF ultrafiltration membrane using polymeric dopamine on the membrane surface. The surface structure and chemical composition of the modified membrane were observed by ESEM and FTIR, respectively. The influence of the modification on the hydrophilicity and wettability of the membrane was characterized by the contact angle and change of the surface of the ultrafiltration membrane with different grafting concentration and grafting time, and the oil emulsion was filtered by the modified membrane. The effects of modification on membrane antifouling performance and retention ability were studied in three simulated wastewater systems of bovine albumin (BSA) and sodium alginate (SA) solution. Finally, the acid-base stability of modified membrane was tested. The results showed that graft functionalization of go reduced the pore size and porosity of the membrane, but enhanced its hydrophilicity and wettability. The hydrophilicity and wettability of the membrane surface increased with the increase of grafting concentration and grafting time, while the pure water flux increased firstly and then decreased with the increase of grafting concentration and grafting time. The average contact angle of the modified PVDF ultrafiltration membrane was 77 擄, and the average contact angle decreased to 61 擄(m ~ (2) h) from 206.8L/ (m ~ (2 路h) to 120.4 (m ~ (2) h). The optimum grafting concentration of GO-NH2 was 2 mg / mL and the grafting time was 60 min. The anti-fouling performance of modified membrane was studied by using three kinds of simulated wastewater systems of oil emulsion BSA and SA. The results showed that the anti-fouling ability of modified membrane was improved. By soaking the modified membrane with acid and alkali, the stability of the modified membrane was tested by using the pure water flux and the contact angle of the membrane surface. The results showed that the modified membrane had good acid resistance, but the alkalinity resistance was relatively weak. Finally, by using 55 鈩

本文編號：2164362