超声对铁氰化钾电化学还原反应速率的影响

THE EFFECT OF ULTRASOUND ON THE REACTION RATE FOR THE ELECTROCHEMICAL REDUCTION OF K_3Fe(CN)_6

分别在有超声和无超声作用下 ,测定了不同温度和反应物浓度下 K3 Fe(CN) 6电化学还原过程的极化曲线和电流密度 .研究结果表明 ,在 K3 Fe(CN) 6电化学还原过程中 ,超声作用可以显著增大过程的传质速度和扩散电流密度 ,在电极电位为 0 .1 5 V(vs SCE)时 ,有超声作用时的电流密度是无超声作用时的2 6倍 ,电极电位为 -0 .3 0 V(vs SCE)时 ,为 65倍 .随着反应体系的温度升高 ,超声空化效应减弱 ,当温度从 2 5℃升高到 65℃时 ,有超声与无超声作用下极限扩散电流密度的比值从 68.4降至 5 4.0 .

The effect of ultrasound on the electrochemical reduction of K_3Fe(CN)_6 to K_4Fe(CN)_6 was studied at different temperatures and reactant concentrations. The experimental results show that the current density is remarkably increased with ultrasound at different temperatures and reactant concentrations in the reduction of K_3Fe(CN)_6 to K_4Fe(CN)_6 system. The electrochemical reduction rate is 26 times at 0.15 V (vs SCE) and 65 times at -0.30 V (vs SCE) under the ultrasound as that without ultrasound. The ratio of current density with ultrasound to that without ultrasound is decreased from 68.4 to 54.0 with increasing operating temperatures because cavitation is decreased with increasing operating temperatures from 25 ℃ to 65 ℃.