物理化学学报 >> 1995, Vol. 11 >> Issue (05): 390-394.doi: 10.3866/PKU.WHXB19950502

研究论文 上一篇    下一篇

琼脂凝胶中形成铬酸铅周期性沉淀的机理研究

张文敏, 董吉溪, 熊言林   

  1. 安徽师范大学化学系|芜湖 241000
  • 收稿日期:1994-04-12 修回日期:1994-09-26 发布日期:1995-05-15
  • 通讯作者: 张文敏

Mechanism of Periodic Presepitation in a Lead Chromate System Containing Agar-agar Gel

Zhang Wen-Min, Dong Ji-Xi, Xiong Yan-Lin   

  1. Department of Chemistry,Anhui Normal University,Wuhu 241000
  • Received:1994-04-12 Revised:1994-09-26 Published:1995-05-15
  • Contact: Zhang Wen-Min

摘要:

选择硝酸铅和铬酸钾作为相互扩散的反应物以形成铬酸铅在琼脂凝胶中的周期性沉淀.分别在光照和黑暗中对六种不同浓度的硝酸铅溶液进行了实验.根据实验现象对周期性沉淀的形成提出了可能的机理.认为光辐射可使铬酸铅部分电离,从而减慢了胶核成长速率,有利于汇聚成带.

关键词: 周期性沉淀, Liesegang现象, 铬酸铅

Abstract:

The Pb(NO3)2 and K2CrO4 were chosen as the interdiffusing electrolytes for periodic precipitation of PbCrO4 in an agar-agar gal. Six series of experiments in which the concentration of Pb(NO3)2 solution was different from another were performed under illumination and dark respectively. On the basis of phenomena of the experiments a possible mechanism of formation of periodic precipitation was reported. It was considered that the PbCrO4 was dissociated partly under the light radiation, the growth velocity of the colloid nuclei was increased, and therefore presence of light was favorable for pattern formation.

 

Key words: Periodic precipitation, Liesegang phenomenon, Lead chromate