不同EDTA添加剂浓度下ZTS溶液诱导期及其成核特性研究

Study on the Induction Period and Nucleation Characteristics of ZTS Solution with Different Concentration of EDTA

测定了25℃下,添加不同浓度的EDTA后,不同过饱和比下ZTS溶液的诱导期,研究了掺杂浓度及过饱和比对ZTS溶液成核的影响。研究显示,当溶液处于较高过饱和比时(S>1.13),均匀成核占主导;而在较低过饱和比时(S<1.11),则以非均匀成核为主。利用经典成核理论对实验所得数据进行分析,计算得到了界面张力、临界核形成功、临界核半径等成核特性,发现了溶液过饱和比及掺杂浓度对成核速度的影响,解释了添加EDTA能提高溶液稳定性的原因。利用界面张力的值计算得到了表面熵因子。

The induction period was measured at 25 ℃ with different doping concentrations of EDTA and supersaturation ratios of ZTS. The effects of doping concentration and supersaturation ratio on nucleation of ZTS solution were studied. The study revealed a homogeneous nucleation region at high supersaturation ratios（ S〉 1. 13） and a heterogeneous nucleation region at low supersaturation ratios（ S〈 1. 11）. The induction time data was analyzed using classical nucleation theory to calculate the interfacial tension,the critical free energy of nucleus,radius of critical nucleus,etc. The effect of supersaturation ratios of solution and doping concentration on nucleation rate was found. The reason of solution stability increases after EDTA doped was also explained. Finally,the surface entropy factor was calculated through the value of interfacial tension.