| 摘要: | 化學需氧量（COD）為環境水體有機污染物含量及水質監測的重要指標之一。 然而，傳統COD 分析方法存在諸多缺點，例如：分析時間長、氧化能力受限、高 毒性試劑的二次污染等。電化學方法相比於傳統方法具有反應迅速、成本低廉、 靈敏度高、選擇性佳以及對環境友善等優點，使其在 COD 分析中，尤其是現場 監測和分析時，逐漸受到重視。
本研究透過溶膠-凝膠法製備二氧化碳/單壁奈米碳管複合材料並用於修飾電 極，以線性掃描伏安法(LSV)對水樣進行 COD 分析，水樣分為單物種水樣及雙物 種水樣。單物種水樣由鄰苯二甲酸氫鉀、對-硝基苯酚、甘胺酸、水楊酸等有機物 所配製而成；雙物種水樣則由前述四種有機物彼此組合，在不同理論需氧量比例 的情況下，探討有機物在電極上的交互作用。結果顯示，製備的電極在單物種水 樣中，在 10-100 mg/L 的濃度區間內，對所有的有機物均表現出良好的相關性； 在雙物種系統中，KHP+SA 溶液的結果顯示，在+0.3 V 處可能存競爭作用，減弱 了SA 二聚體的氧化反應，並增強了SA 在+0.7 V 及+1.1 V 的氧化電流。在KHP+4- NP 溶液中，由於 KHP 的電催化氧化電流減少，因此推估 4-NP 抑制了 KHP 在電 極表面的吸附，而芳香族間的協同作用使得4-NP 的氧化電流增加。此外，4-NP+SA 溶液的結果顯示，兩物種間可能存在競爭作用，使得 4-NP 的氧化電流升高，並 減弱了SA 的氧化。最後，SA+甘胺酸的溶液顯示，兩物種間可能存在競爭作用，導致兩者的反應電流均減少。;Chemical oxygen demand (COD) is a critical indicator for assessing the organic pollutant levels in environmental water bodies and is widely used for water quality monitoring. However, traditional COD analysis methods have several drawbacks, including time-consuming, limited oxidation capability, and secondary pollution due to the use of highly toxic reagents. In contrast, electrochemical methods offer several advantages, such as rapid analysis, low cost, high sensitivity, excellent selectivity, and environmental friendliness, making them increasingly attractive for COD analysis, especially for on-site monitoring and analysis.
In this study, TiO2/SWCNT nanocomposites were synthesized using the sol-gel method and utilized to modify electrodes for COD analysis using linear sweep voltammetry (LSV). Both single-species and dual-species water samples were investigated. The single-species samples were prepared using potassium hydrogen phthalate (KHP), 4-nitrophenol (4-NP), glycine, and salicylic acid (SA), while the dual- species samples were composed of two compounds mentioned above. The study discussed the interactions between organic species on the electrode under varying theoretical oxygen demand (ThOD) ratios.
The results demonstrated that the prepared electrodes exhibited excellent correlation for all organic compounds in single-species systems in a concentration range of 10-100 mg/L. In dual-species systems, the KHP+SA mixture revealed potential competitive interactions at +0.3 V, weakening the oxidation of SA dimers while increasing the oxidation currents of SA at +0.7 V and +1.1 V. For the KHP+4-NP mixture, the oxidation current of KHP was reduced and that of 4-NP enhanced, which suggested that 4-NP inhibited the adsorption of KHP onto the electrode surface, and there might be synergistic effects between 4-NP aromatic groups. Additionally, there was competition between 4-NP and SA in the mixture, which lead to an increased oxidation current of 4-NP and a decrease in the oxidation current of SA. Finally, both oxidation currents of SA and glycine reduced after they were mixed, which suggested that there might be competition. |
