奈米薄膜去除天然有機物與微囊藻毒-LR之研究

Removal of NOMs and Microcystin-LR by NF Membrane

盛佑鼎(You-Ding Sheng)

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(2008年)

https://doi.org/10.6342/NTU.2008.02851

摘要

由於薄膜對於微量污染物與天然有機物具有非常高的去除能力。因此近年來，薄膜技術被選為為淨水流程的高級處理技術，使飲用水水能符合嚴格的飲用水質標準。
本篇論文主要探討的方向有兩個(1)UF/NF薄膜對於天然有機物與微囊藻毒-LR的去除效率與機制(2)使用薄膜技術控制三鹵甲烷的生成趨勢(THMFP)。
從實驗結果得知，天然有機物中的疏水性物質由於比親水性物質具有較高的UV254與SUVA值，因此疏水性物質具有較顯著的芳香族特性。薄膜處理疏水性物質時，DOC 去除率高達96%且DOC殘留濃度非常低(小於0.2ppm)。此外，薄膜於不同操作壓力下，親水性物質對於UV254的去除率達80~85%，疏水性則為95~98%。
經過24小時操作結果顯示，與疏水性物質相較之下，親水性物質的通量衰減程度較高，因此具較高積垢生成的趨勢。但從GFC分子量分布圖顯示，不管是親水性或疏水性物質，其中具低濃度與低分子量(350Da~500Da)的物質均會通過薄膜，所以無法完全被去除。
微囊藻毒-LR的去除成效與天然有機物結果相似(在薄膜高壓的操作條件下，有高的去除效果)。由於積垢沉澱模式、孔阻塞模式與吸附模式均具有很高的相關係數，因此這三種模式可被假設為造成薄膜積垢的主要機制。

關鍵字

天然有機物 ； 超過濾 ； 奈米過濾 ； 三鹵甲烷生成趨勢 ； 親水性物質 ； 疏水性物質 ； 微囊藻毒LR

並列摘要

In recent years, membrane filtration has been considered as an advanced water treatment technology, able to provide drinking water to meet stringent drinking water regulations. Membrane processes are often chosen to achieve a high removal of micropollutants and NOMs.
As a result, the purposes of this study include: (1) the investigation of the removal efficiencies and mechanisms of NOMs and Microcystin-LR by the ultra-filtration (UF) and nano-filtration(NF) membranes, and (2) the control of trihalomethane formation potential (THMFP) in Tai-Lake source water through the membrane process.
The results of this research work indicate that the hydrophobic substances exhibit higher aromaticity of NOMs than the hydrophilic substances because of their higher UV254 and SUVA values. For the hydrophobic substance, the DOC removal efficiency was over 96% and residual DOC concentration was very low (below 0.2 ppm). The UV (254 nm) absorbance reductions rejection ratio was 80~85% for hydrophilic substances and 95~98% the hydrophobic at various operating pressures.
The hydrophilic substance caused a higher fouling potential than the hydrophobic substance over the 24 hour operation. From the GFC diagram, both the hydrophilic and hydrophobic water samples (fractionated form DAX-8 resin) could not be removed by the NF membrane process completely because the diffusion of low concentration DOC with a low molecular weight distribution(350~500 Da).
The tendency for removal of microcystin-LR (MC-LR) was similar to that of NOMs rejection (i.e. the higher pressure operation reveals better removal efficiency). The high correlation coefficients in the cake deposit model, the pore blocking model and adsorption model suggest that the three mechanisms should cause fouling in membrane process.

並列關鍵字

Natural organic matters (NOMs) ； ultra-filtration (UF) ； nano-filtration (NF) ； THM formation potential (THMFP) ； hydrophilic substance ； hydrophobic substance ； microcystin-LR (MC-LR)

參考文獻

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