胺官能化氧化石墨烯/幾丁聚醣混成奈米過濾薄膜之研究

為增加薄膜之孔隙度，本研究以PEG 200作為造孔劑，加入PSf高分子溶液中，利用濕式相轉換法製備非對稱多孔隙PSf基材膜。為製備正電荷奈米過濾薄膜，本研究將氧化石墨烯進行胺官能化，使其電性由負電轉為正電，添加於以戊二醛(GA)交聯的幾丁聚醣(CS)溶液，將其刮鑄於PSf基材膜上，製備胺官能化氧化石墨烯/幾丁聚醣(NGO/CS-GA)混成薄膜，應用於奈米過濾分離鹽類水溶液。本研究探討製膜條件(幾丁聚醣之去乙醯程度、交聯劑濃度、無機材添加量、旋轉塗佈之轉速等)、製膜方式(溶液塗佈法、旋轉塗佈法)、胺官能化氧化石墨烯改質方式(包括偶合劑與胺單體類型)以及奈米過濾操作條件(包括進料濃度、進料pH值、鹽類類型與抗垢能力)對薄膜特性與分離效能之影響。本研究亦使用全反射傅立葉紅外光譜(ATR-FTIR)分析薄膜與無機材料的化學結構，以場發射掃描式電子顯微鏡(FESEM)觀察薄膜表面與截面之結構型態，利用X射線光電子能譜儀(XPS)分析薄膜的化學組成，以確認薄膜交聯程度變化，以原子力顯微鏡(AFM)實驗觀察薄膜表面粗糙度。研究結果顯示，包含1.5 wt% CS(DD=80%)、5 wt% PEHA-GO(以CS重量為基準)與0.6 wt% GA(交聯劑)的鑄膜液，以轉速4000 rpm之旋轉塗佈法所製備的薄在具有最佳的奈米過濾效能，其純水通量為8 L/m2h，對MgCl2的阻鹽率為91%，其對無機鹽類的阻鹽率由高至低依序為：氯化鎂 > 硫酸鎂 > 氯化鈉 > 硫酸鈉，此為一典型正電荷奈米過濾薄膜之效能。在抗垢測試實驗中，分別使用正電荷的CTAB與負電荷的BSA的鹽類水溶液做為進料進行測試，PGO/CS-GA薄膜皆具有約90%的通量回復率。

關鍵字

胺官能化氧化石墨烯；幾丁聚醣複合薄膜；奈米過濾

並列摘要

In order to increase the porosity of PSf membrane, the asymmetric porous PSf was prepared by wet phase inversion method using the casting solution with PEG 200 as pore forming agent. To fabricate a positively charged nanofiltration membrane, graphene oxide was functionalized by amine monomer. The amino-functionalized graphene (NGO) was incorporated into chitosan (CS) polymer solution crosslinked by glutaraldehyde (GA). Then this solution was cast onto PSf support membrane to fabricate amino-functionalized graphene oxide/chitosan (NGO/CS-GA) hybrid membrane. This membrane was applied to nanofiltration for aqueous salt solution. The effects of membrane fabrication condition (degree of deacetylation of chitosan, concentration of glutaraldehyde, NGO loading, and spin rate), membrane fabrication method (solution casting and spin coating), and amino-modified process of graphene oxide (types of coupling agent and monomer), and nanofiltration operating condition (feed concentration, feed pH value, type of inorganic salt, and anti-fouling) on the characteristics and separation performance of membrane was investigated systematically. Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy and field emission scanning electron microscope (FESEM) were used to characterize the chemical structure and morphology of membrane, respectively. The effect of GA concentration on crosslinking degree of membrane was characterized by X-ray photoelectron spectroscopy (XPS). The roughness was analyzed by atomic force microscopy (AFM). NGO/CS-GA composite membrane prepared by spin-coating method with spin rate of 4000 rpm using the casting solution composed of 1.5 wt% CS(DD=80%), 0.6 wt% GA, and 5 wt% PEHA-GO(based on CS by weight) showed the best nanofiltration performance. The pure water flux was 8 L/m2h and rejection to MgCl2 was 91%. The order of rejection to inorganic salts was MgCl2 > MgSO4 > NaCl > Na2SO4. This trend was similar with most positively charged nanofiltration membrane in the literature. In the antifouling experiment, both positively charged foulant (CTAB) and negatively charged foulant (BSA) were dissolved in MgCl2 solution as feed solution. The flux recovery ratio of PGO/CS-GA composite membrane were about 90%.

並列關鍵字

amino-functionalized graphene oxide ； chitosan composite membrane ； nanofiltration

參考文獻

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胺官能化氧化石墨烯/幾丁聚醣混成奈米過濾薄膜之研究

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