酸性溶液中不同电位下脆硫锑铅矿/DDTC界面的电化学机制

用循环伏安和交流阻抗法,研究了脆硫锑铅矿在含乙硫氮的pH 4.0缓冲溶液中的表面电化学行为,讨论了在不同电位下脆硫锑铅矿表面的反应、电化学吸附、钝化作用、电化学阻抗、微分电容的变化.结果表明:在酸性溶液中,脆硫锑铅矿具有盐的特性;电极过程呈现出受电化学反应及产物吸附控制的动力学特征.当电极电位为-78 mV～422 mV,矿物表面疏水性膜逐渐增长并产生钝化作用;当电极电位为522 mV时,电极过程完全由离子扩散决定的电化学反应所控制;当电位大于622 mV后,电极反应产生大量的PbSO4沉淀,并覆盖在电极表面,矿物表面的亲水性强.

MECHANISM OF ELECTROCHEMISTRY OF JAMESONITE/DDTC INTERFACE IN ACIDIC SOLUTION

Electrochemical behaviors on the surface of jamesonite in an acidic solution of pH4.0 buffer solution containing diethyl dithiocarbamate were investigated by the methods of cyclic voltammetry and AC impedance. The changes of the reactions, electrochemical adsorption, passivation action, electrochemical impedance and interfacial capacitance on jamesonite were discussed under the different conditions of electrode potentials. In the acidic solution, jamesonite is of a salt characteristics, and its electrode process kinetics is controlled by the electrochemical reactions and the adsorption of their productions. The hydrophobic adsorption film gradually grows and passivates on jamesonite from - 78 mV to 422 mV. The electrode process of jamesonite at 522 mV is quite controlled by the reaction that is depended on ion diffusion. When the electrode potential is over 622 mV, the hydrophilicity on jamesonite becomes strong due to covering an amount of PbSO4 from the electrochemical reactions.