苯酚磺酸中酚羟基对锡电解精炼过程的影响

苯酚磺酸气味大、对人体有害，亟需开发新型绿色添加剂替代苯酚磺酸。采用溶氧仪、恒流极化、线性电位扫描、扫描电子显微镜等对比研究了锡电解精炼过程中苯酚磺酸、甲苯磺酸对溶解氧浓度、Sn2+稳定性、Sn2+沉积动力学、阴极锡形貌、电流效率的影响，解析了酚羟基的作用机制。结果表明，酚羟基具有还原性，可以降低电解液溶解氧浓度，进而抑制Sn2+氧化水解，减缓Sn2+的贫化，有利于提高电流效率。此外，酚羟基可以改变Sn2+沉积反应路径，阻滞Sn2+阴极沉积，增大阴极极化，进而获得平整致密的阴极锡。

Effect of Phenolic Hydroxyl Group in 4-hydroxybenzenesulfonic Acid on Tin Electrorefining Process

4-hydroxybenzenesulfonic acid (HBSA) has a strong odor and is harmful to human body. It is urgent to develop novel green additive to replace HBSA. Effects of HBSA and 4-methylbenzenesulfonic acid (MBSA) on dissolved oxygen concentration, Sn2+ stability, Sn2+ deposition kinetics, cathodic tin morphology and current efficiency during tin electrorefining process were investigated and compared through dissolved oxygen meter, galvanostatic polarization, linear sweep voltammetry and scanning electron microscope. The results show that phenolic hydroxyl groups is reductive, which can reduce the concentration of dissolved oxygen in electrolyte, inhibit the oxidative hydrolysis groups of Sn2+, and further relieve the depletion of Sn2+. This is beneficial to enhance current efficiency of tin electrorefining process. In addition, phenolic hydroxyl groups can regulate Sn2+ deposition path, impede Sn2+ cathode deposition, and further enlarge cathode polarization, which could contribute to a larger flatness and compactness of cathodic tin.