PbO2/Ti阳极氧化苯酚的有效电流表征及阶段反应动力学

来源期刊:中南大学学报(自然科学版)2017年第10期

论文作者:王立章 伍波 李鹏 赵玉 李哲楠 杨胜翔 赵跃民

文章页码:2583 - 2590

关键词:PbO2/Ti;阳极氧化;有效电流;阶段反应动力学;苯酚

Key words:PbO2/Ti; anodic oxidation; effective current; step-reaction kinetics; phenol

摘    要:采用X线衍射(X-ray diffraction, XRD)和扫描电镜(scanning electron microscope, SEM)对以电镀法制备的PbO2/Ti阳极进行表征,以阳极氧化电流占比系数γ描述苯酚氧化与析氧反应之间的影响机制,并基于法拉第定律建立描述有机物氧化进程的通用阶段反应动力学模型;在不同电流密度和进水流量条件下进行苯酚阳极氧化实验。研究结果表明:电极表面晶相主要为β-PbO2,晶粒平均直径为50.23 nm,形成的团聚体粒径在5~10 μm之间。PbO2/Ti阳极析氧电位约为1.78 V;液相中苯酚的存在可抑制氧气析出,且析氧反应电阻由无苯酚情况下的148.3 Ω增大至195.9 Ω。回归分析和F检验结果证明理论预测值与实验数据之间具有一致性。

Abstract: The electroplating method was employed for preparation of PbO2/Ti anode, which was determined by the X-ray diffraction (XRD) analysis and scanning electron microscope (SEM) characterization. A novel parameter γ, defined as fractional current applied to effective oxidation was proposed to describe the relation between the oxygen evolution and anodic oxidation of organic compounds. Then, step-reaction kinetics was achieved via Faraday’s law by introducing the parameter γ. Phenol electro-oxidation experiment was carried out at different applied current densities and flow rates. The results show that the main content of the coating material on Titanium (Ti) is β-PbO2 with average crystal size is about 50.23 nm, and these grains can effectively grow to form aggregate with particle size of 5 μm to 10 μm even dispersed on the Ti plate. The oxygen evolution potential of the prepared PbO2/Ti anode is 1.78 V or so, and phenol can decrease oxygen evolution rate by increasing the resistance of water decomposition to 195.9 Ω, which is much higher than that in Na2SO4 solution (148.3 Ω). The regressive analysis and F-test results confirm that the model prediction can satisfactorily match the experimental data.

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