有機物質對電容去離子之影響

The Impact of Organic Matters on Capacitive Deionization (CDI)

王映叡(Ying-Jui Wang)

指導教授 ： 彭晴玉

淡江大學/工學院/水資源及環境工程學系碩士班/碩士(2021年)

https://doi.org/10.6846/TKU.2021.00661

摘要

水資源短缺已成為全球關注的議題。電容去離子(CDI)是一種新興的離子去除技術，用於去除水中離子。有機物的存在會阻塞CDI電極並導致CDI效能下降。本研究中，使用三種電極材料：粒狀活性碳電極(GAC)、經硫酸改質的粒狀活性碳(SGAC)、抗阻塞膜/粒狀活性碳電極(PVDF /GAC或PES/GAC)，探討有機物(腐殖酸(HA)或天然有機物(NOM))對CDI系統的影響。
實驗結果顯示有機物的存在會顯著降低GAC電極的電吸附能力。由於NOM的化學結構比HA更複雜，因此NOM對CDI效能的負面影響更大。在HA或NOM存在的情況下， GAC電極的平均電吸附容量分別從3.88 mg/g降至3.04或2.94 mg/g，分別降低了21.6％或24.2％。
經過硫酸改質後之粒狀活性碳(SGAC)，SGAC電極的平均電吸附量提高到4.44 mg/g。在HA或NOM存在的情況下，平均電吸附量分別降低至3.62或3.36 mg/g，相當於降低了18.5％或24.3％。
GAC電極上的抗組塞膜(PVDF或PES)可以減輕有機物阻塞的影響。特別是PVDF/GAC電極，不僅提高了平均電吸附容量，而且抑制了HA或NOM對CDI效能的影響。應用於CDI系統的PVDF/GAC電極的平均電吸附容量為4.83 mg/g。即使溶液中存在HA或NOM，平均電吸附容量仍可以保持在較高的水平(4.55或4.26 mg/g)。研究成果顯示PVDF或PES膜的親水特性可有效防止有機物阻塞。

關鍵字

電容去離子、有機物質、活性碳、硫酸改質、抗有機膜、電極阻塞

並列摘要

Water shortage has become a global concern. Capacitive Deionization (CDI) is an emerging ion separation technology for removal of ions from water. The presence of organic matters will foul on the CDI electrode and lead to the decline of the CDI performance. In this study, three kinds of electrode materials: granular activated carbon electrode (GAC), granular activated carbon modified by sulfuric acid electrode (SGAC), antifouling membrane/granular activated carbon electrode (PVDF/GAC or PES/GAC) were used in CDI systems to investigate the impact of organic matters (humic acid (HA) or NOM) on CDI system.
Our results showed that the presence of organic matters can significantly reduce the electrosorption capacity of GAC electrode. NOM has more adverse impact on CDI performance due to more complex chemical structures than that of HA. The average electrosorption capacity of GAC electrode during CDI processes decreased from 3.88 mg/g to 3.04 or 2.94 mg/g in the presence of HA or NOM, respectively, which corresponding to 21.6% or 24.2% reduction.
With sulfuric acid modification, the average electrosorption capacity of SGAC electrode was improved to 4.44 mg/g. In the presence of HA or NOM, the average electrosorption capacity diminished to 3.62 or 3.36 mg/g, respectively, which corresponding to 18.5% or 24.3% reduction.
The antifouling membrane (PVDF or PES) coating on GAC electrode can mitigate the impact of organic matters fouling. Especially for PVDF/GAC electrode, not only the average electrosorption capacity was raised, but also the impact of HA or NOM on CDI performance was damped. The average electrosorption capacity of PVDF/GAC electrode applied to CDI system was 4.83 mg/g. Even with HA or NOM presented in the solution, the average electrosorption capacity can remain at high level (4.55 or 4.26 mg/g). The hydrophilic characteristics of PVDF or PES membrane were proved to effectively prevent the fouling of organic matters.

並列關鍵字

Capacitive deionization, Organic matters, Activated carbon, Sulfuric acid modified, Antifouling membrane, Electrode fouling

參考文獻

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