以鉑電極活化過硫酸鹽去除水中1,4-二氧陸圜機制之研究

本研究以雙鉑電極活化過硫酸鹽氧化法處理廢水中1,4-二氧陸圜(1,4-Dioxane)與偶氮染料酸性橙(Acid Orange 7, AO7)，反應系統由陽極槽及陰極槽組成，兩槽以陽離子交換膜區隔，以利評估陽極及陰極於電化學過硫酸鹽系統中去除污染物所扮演之角色。本研究主要目的為：(1)評估不同電壓對過硫酸鹽活化之影響；(2)評估不同電壓對過硫酸鹽去除水中AO7及1,4-Dioxane之影響；(3)評估單槽與雙槽系統去除污染物之差異；及(4)探討電活化過硫酸鹽系統中自由基生成物種及污染物降解機制。電活化過硫酸鹽實驗結果顯示，施加不同電壓對過硫酸鹽分解效率為10 V > 7 V > 5 V > 3 V，顯示伏特值越高時過硫酸鹽分解效率越佳。在不同伏特數下對AO7與1,4-Dioxane之降解實驗結果顯示，AO7降解效率在10V比其他伏特數高，顯示施加高電壓時陰極提供之電子可有效活化過硫酸鹽，而在陽極氧化作用下，產生的氫氧自由基去除AO7的效率在高伏特數下亦優於低伏特數。在使用50 mM氧化劑與10 V條件下，反應時間4小時後，1,4-Dioxane於陰極之去除效率為62.6%，於陽極之去除效率為90.3%。實驗結果顯示，雙鉑電極於高伏特數時對去除1,4-Dioxane效率極佳，且陽極氧化污染物能力較陰極優越。該電化學活化過硫酸鹽的系統中受限於許多因子，可能使實驗較為不穩定，但在應用上仍有一定的潛力。本研究成果將有助於提升電化學氧化法未來應用之可行性。

關鍵字

1,4-二氧陸圜；偶氮染料酸性橙；電化學過硫酸鹽氧化法；鉑電極

並列摘要

In this study, two platinum electrodes were applied to activate persulfate for the treatment of 1,4-dioxane and Acid Orange 7 (AO7). A cation exchange membrane was used to separate the anode and the cathode compartments to evaluate the roles of anode and cathode in the degradation of the contaminants. The main objectives of this study were to: (1) evaluate persulfate activation at different voltages and concentrations; (2) evaluate the effect different voltages on the removal of AO7 and 1,4-dioxane by electrode-activated persulfate; (3) compare the difference in the contaminant removal between single- and two-compartment systems; and (4) determine free radical species and degradation mechanisms of the pollutants in the electrochemical persulfate systems. The experimental results show that the degradation efficiency of persulfate at different voltages was 10 V > 7 V > 5 V > 3 V, which proved that persulfate could be activated by the platinum electrode. The results of AO7 and 1,4-dioxane degradation experiments show that the degradation efficiency of AO7 at 10 V was higher than that of other volts. When high voltage was applied, sulfate free radicals were produced by the electrons provided by the cathode and hydroxyl radicals generated by anodic oxidation, which contributed the degradation of AO7. Under the condition of using 50 mM persuflate and 10 V, the removal efficiency of 1,4-dioxane in the adnode and cathode compartments was 90.3 and 62.6%, respectively. The experimental results show that good performance of electrochemical persulfate for the degradation of 1,4-dioxane was achieved at high volts and anode had a better ability to oxidize pollutants than cathode. The results of this research will be helpful to enhance the feasibility of the application of electrochemical oxidation in the future.