| Summary: | 碩士 === 國立中央大學 === 環境工程研究所 === 103 === Chemical oxygen demand (COD) indicates the degree of water pollution by organic compounds and is usually monitored. There are still several problems in the analysis of COD. For example, COD may be underestimated because some nitrogenous organic compounds cannot be oxidized by K2CrO7 or when the organic pollutants are volatile. Analysis of COD via voltammetry using TiO2/SWCNT modified glassy carbon electrode is developed in this work. COD standard (potassium hydrogen phthalate, KHP), modeled COD samples (i.e., glucose, TMAH, MEA and oxalic acid), and wastewater from the water treatment plant are used to investigate the response of the oxidation peak currents to the concentration of COD. It was found that the oxidation peak current had linear relationship to the concentration of COD and such relationship was dependent on the concentration. That is, the linearity were different in 10~100 mg/L and 150 ~ 500 mg/L. For glucose, such relationship was only good when the COD concentration was lower than 100 mg/L. Because the oxidations of TMAH and MEA are adsorption-controlled, the oxidation peak current decreased with increasing TMAH or MEA concentration. However, when TMAH and MEA were added into the TFT-LCD wastewater, the oxidation peak current increased with increasing TMAH or MEA concentration. Voltammetry of wastewater from water treatment plant showed similar results to standard COD analysis method, which suggests that analysis of COD via voltammetry using TiO2/SWCNT modified GCE electrode is a promising technique.
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