黏土礦物層面電荷在苯二酚電化學行為之影響

Effects of Layer Charges of Clay Minerals on Electrochemical Behavior of Benzenediols

10.6730/JAAT.201409_15(3).0003

朱家瑩(Chia-Ying Chu)；陳鴻基(Horng-Ji Chen)；曾志明(Jyh-Myng Zen)

黏粒修飾電極 ； 苯二酚 ； 電化學分析 ； clay-modified electrode ； benzaClay-modified electrode ； Benzenediols ； Electroanalysisenediols ； Electroanalysis

台灣農學會報

15卷3期（2014 / 09 / 01）

276 - 296

繁體中文

苯二酚是土壤中常見的酚類化合物，土壤中的黏土礦物對酚類化合物的催化聚合與轉化反應常是土壤腐植質先驅物形成的關鍵。本研究目的以不同黏土礦物修飾網版印刷碳電極（SPCE）配合電化學分析法進行苯二酚電化學分析以了解黏土礦物層面電荷在苯二酚電化學行為之影響。試驗結果指出，六種黏粒修飾SPCE對對苯二酚均能測到兩個還原波峰（R_1、R_2）與兩個氧化波峰（O_1、O_2），且其中以2:1型膨潤石類（SHCa-1、SWy-1及SWa-1）測到的R1波峰電流量較大。SPCE經預氧化處理後（SPCE）再修飾六種黏粒對對苯二酚測到的氧化還原波峰電流量均有明顯增大的現象，且其中以R_2和O_2氧化還原波峰對增大及波峰電位偏移的情形較為明顯。由於兩個羥基在苯之鍵結位置上的不同，使六種黏粒修飾SPCE對對苯二酚與鄰苯二酚所測到的氧化還原波峰形狀和電流量不同，且其對兩種苯二酚共存溶液測到的R_2波峰形狀比兩種苯二酚各別測到的R_2波峰形狀更為駝形。六種黏粒修飾SPCE對兩種苯二酚共存溶液測到的R_2波峰呈現兩個還原波峰，表示對苯二醌與鄰苯二醌分別在不同電位處進行還原反應，此證明預氧化後的氧化層膜對對苯二醌與鄰苯二醌的作用不同，且其受到不同黏土礦物層面電荷所影響，所以在偵測到的循環伏安圖與波峰電流量上會不同。

Benzenediols are common phenolic componds in soils. The catalytic polymerization and transformation of phenolic compounds, a key process in the formation of the precursors of soil humus, are significantly affected by clay minerals. This study investigated the redox behavior of benzenediols with different clay-modified screen-printed carbon electrodes (SPCE) to understand the effects of layer charges on different clay minerals. The results indicated that two reductive peaks (R_1, R_2) and two oxidative peaks (O_1, O_2) were observed in all six claymodified SPCEs with higher R_1 peak currents from SHCa-1, SWy-1 and SWa-1. Preanodization of SPCE (SPCE) further increased the peak currents of R_2 and O_2. The differences in cyclic voltammograms at six clay-modified SPCEs for hydroquinone and catechol originated from different bonding sites of the two hydroxyl groups on the benzene. The peak shapes of R_2 in respective solutions were broader than those detected in six clay-modified SPCEs. The preanodized oxidative layer further caused different cyclic voltammograms with varying reduction potentials and peak currents between p-benzoquinone and o -benzoquinone that were affected by different layer charges of clay minerals.