以奈米薄膜處理含標的藥物及個人保健用品水溶液之研究

Removal of Target PPCPs in Aqueous Solution using NF Membranes

趙國凱(Kuo-Kai Chao)

指導教授 ： 蔣本基

國立臺灣大學/工學院/環境工程學研究所/碩士(2013年)

https://doi.org/10.6342/NTU.2013.01478

摘要

在本研究中，系統性地研究了所選出的四個在水環境中常見的藥物及個人保健用品 (acetaminophen, carbamazepine, sulfamethoxazole, 和naproxen)，經過奈米薄膜NF270掃流式過濾後的去除率。水中酸鹼值對於目標汙染物的去除率的影響，在酸鹼值4到10的範圍內試驗。除此之外，腐植酸和褐藻酸鈉被選為模型有機積垢物，用以研究薄膜積垢對於目標汙染物去除率的影響。並且，鈣和有機積垢物的交互作用，在本研究中也一併納入考量。
研究結果顯示，經腐植酸或褐藻酸積垢的奈米薄膜NF270，皆比清淨的薄膜，具有較高的疏水性。除此之外，清淨膜面的界達電位，在酸性的水中酸鹼值範圍內，有著劇烈的變化。且離子強度是影響膜面界達電位的重要因子。
對於在中性水中酸鹼值範圍內帶負電的化合物，也就是sulfamethoxazole和naproxen而言，當水中酸鹼值接近其酸解離常數時，水中酸鹼值對去除率的影響顯得相當重要。而有機積垢物和鈣的影響，會造成中性化合物去除率的改變，特別是疏水中性的化合物，carbamazepine。
清淨奈米薄膜NF270吸附所選的藥物及個人保健用品，其結果分為三類。第一類是在水中酸鹼值為10時，四種目標藥物都呈現有限的吸附能力，皆低於0.06微克/平方公分；第二類為水中酸鹼值範圍為5到9時，疏水中性的carbamazepine為主要吸附到清淨膜面的藥物。且在水中酸鹼值為7時，有最大的吸附能力0.22微克/平方公分；第三類是水中酸鹼值為4時，主要吸附到清淨膜面的藥物為naproxen，具有0.57微克/平方公分的吸附能力。這結果可歸因於在水中酸鹼值為4時，中性的naproxen成為主要的物種，而不再是解離帶負電的naproxen，且較其他藥物具有更高的疏水性，其正辛醇/水分配係數為3.18。

關鍵字

奈米薄膜過濾 ； 藥物及個人保健用品 ； 吸附能力 ； 腐植酸 ； 褐藻酸鈉

並列摘要

In this study, the rejection of four selected compounds (acetaminophen, carbamazepine, sulfamethoxazole, and naproxen) by cross-flow nanofiltration using membrane NF270 was systematically investigated. These compounds, pharmaceutical and personal care products, are ubiquitous in the aquatic environment. The effect of pH on rejection of target compounds was also conducted in the range between 4 and 10. Furthermore, the effect of organic fouling on rejection of selected compounds was studied using humic acid and sodium alginate as model organic foulants. Besides, the interaction between organic foulants (humic acid and sodium alginate) and calcium was also considered in this research.
The results show that NF270 membrane fouled by humic acid and by alginate became more hydrophobic than clean membrane, regardless of which organic foulant was present. Furthermore, zeta potential of clean NF270 membrane surface dramatically changed around the acidic pH range. Moreover, ion strength is a key factor in affecting zeta potential of membrane surface.
For negatively charged compounds, namely sulfamethoxazole and naproxen, at neutral pH range, pH played an important role in rejection, especially when pH was near the pKa of the target compounds. The organic foulants and calcium could affect the rejection of organic compounds, especially the hydrophobic and neutral carbamazepine.
Results of the adsorption of selected PPCPs on clean NF270 membrane as a function of pH was can be divided into three groups according to the pattern of figure. In group Ⅰ, all four compounds have limited adsorption capacity at pH 10, and the adsorbed mass was less than 0.06 μg/cm2 for each compound. In group Ⅱ, hydrophobic and neutral compound, CBZ, was the major compound adsorbed among all four selected compounds at pH range between 5 and 9. In addition, the mass of CBZ adsorbed on clean NF270 membrane was maximum at pH 7, where the adsorbed mass of CBZ was 0.22 μg/cm2. In group Ⅲ, naproxen became the major compound adsorbed with an adsorption density of 0.57 μg/cm2 at pH 4. This result could be attributed to the neutral NAP species being a dominant species at pH 4, and its relative high hydrophobicity with 3.18 of Log Kow compared to other compounds.

並列關鍵字

nanofiltration ； pharmaceutical and personal care products ； adsorption capacity ； humic acid ； sodium alginate

參考文獻

Bellona, C., J. E. Drewes, P. Xu & G. Amy (2004) Factors affecting the rejection of organic solutes during NF/RO treatment—a literature review. Water Research, 38, 2795-2809.

Bound, J. P. & N. Voulvoulis (2006) Predicted and measured concentrations for selected pharmaceuticals in UK rivers: Implications for risk assessment. Water Research, 40, 2885-2892.

Bowen, W. R., A. W. Mohammad & N. Hilal (1997) Characterisation of nanofiltration membranes for predictive purposes — use of salts, uncharged solutes and atomic force microscopy. Journal of Membrane Science, 126, 91-105.

Comerton, A. M., R. C. Andrews & D. M. Bagley (2009) The influence of natural organic matter and cations on the rejection of endocrine disrupting and pharmaceutically active compounds by nanofiltration. Water Research, 43, 613-622.

Comerton, A. M., R. C. Andrews, D. M. Bagley & C. Hao (2008) The rejection of endocrine disrupting and pharmaceutically active compounds by NF and RO membranes as a function of compound and water matrix properties. Journal of Membrane Science, 313, 323-335.