Zn^(2+)-S^(2-)-H_2O系热力学平衡研究  

Thermodynamic Equilibrium of Zn^(2+)-S^(2-)-H_2O System

作　　者：李二平[1] 闵小波[1] 舒余德[1] 王云燕[1] 柴立元[1] 

机构地区：[1]中南大学冶金科学与工程学院,湖南长沙410083

出　　处：《环境科学与技术》2010年第3期1-3,8,共4页Environmental Science & Technology

基　　金：国家自然科学基金(50508044);国家自然科学基金重点项目(50830301);国家科技支撑计划重点项目课题(2007BAC25B01);教育部科技重大项目(308019);湖南省自然科学基金(08JJ3020);湖南省科技计划项目(2008SK4031);湖南省节能减排科技重大专项(08SK1005&08SK1002)

摘　　要：根据配位化学热力学平衡原理,绘制了温度为298.15K时Zn2+-S2--H2O系pC-pH热力学平衡状态图。结果表明:ZnS溶解平衡时,随着pH值的增加,ZnS的溶解度先减少后增加,当pH值为8.36时,ZnS的溶解度最小,为10-7.69mol/L;Zn(OH)2溶解平衡时,随着pH值的增加,Zn(OH)2的溶解度也呈现先减少后增加,当pH值在9.41时Zn(OH)2的溶解度最小,为10-5.61mol/L;体系中ZnS和Zn(OH)2二者固相溶解平衡时,当S2->Zn2(+mol)时,pH在0～14范围内只生成ZnS沉淀,不会产生Zn(OH)(2s)物质。研究结果可为硫化沉淀法去除废水中锌等技术提供理论依据。pC-pH diagrams of Zn^2＋-S^2--H2O system at 298.15K were calculated and drawn according to the theory of thermodynamic equilibrium. When dissolution of ZnS was in equilibrium, the solubility of ZnS firstly decreased and then increased with pH value increased. ZnS solubility of 10^-769mol/L was the minimum at pH value of 8.36. In the dissolution equilibrium system of Zn （OH）2, relationships between the solubility of Zn （OH）2 and pH values showed the same laws as ZnS, and Zn （OH）2 had the minimum solubility of 10^-561 mol/L when pH value was about 9.41. In dissolution equilibrium system of Zn（OH）2 and ZnS, when sulfide ion concentration exceeded zinc ion and pH value ranging from 0 to 14, only ZnS precipitation generated. Results can provide a theoretical basis for the technology for removal of zinc ion from wastewater by sulphurization precipitation method.

关 键 词：Zn2+-S2--H2O系 热力学平衡 pC-pH图 溶解度 

分 类 号：X12[环境科学与工程—环境科学]