流动CO_2-H_2O系统中方解石溶解动力学机制——扩散边界层效应和CO_2转换控制  

Dissolution Kinetics of Calcite in CO_2-H_2O Solutions in Turbulent Flow:The Role of the Diffusion Boundary Layer and the Slow Reaction CO_2+H_2O H^++HCO_3^-

作　　者：刘再华[1] Wolfgang Dreybrodt 

机构地区：[1]中国地质科学院岩溶地质研究所,桂林541004 [2]不来梅大学物理系

出　　处：《地质学报》1998年第4期340-348,共9页Acta Geologica Sinica

基　　金：国际地质对比计划IGCP 379项目;国家自然科学基金(编号 49632100;49703047);地质矿产部"九五"重点科技项目(编号9501104)和地质矿产部岩溶动力学开放研究实验室联合资助

摘　　要：利用旋转盘实验装置和高分子生物催化剂技术,笔者研究了流动CO_2-H_2O系统中方解石溶解动力学及其控制机制。实验发现,方解石的溶解既受到固-液界面间扩散边界层(DBL)的控制,还受到扩散边界层内CO_2慢速转换反应(CO_2+H_2OH^+HCO_3^-)的控制。然而,高CO_2分压(P_(CO_2)>0.01 atm)时,溶解主要为CO_2慢速转换控制,而低CO_2分压(P_(CO)_2<0.01atm)时,溶解主要为扩散边界层控制。对于这些发现,利用DBL理论模型进行了成功的解释。By making use of the rotating disc apparatus and macromolecular biocatalyst, the authors have studied the kinetics of calcite dissolution in CO2-H2O solutions with turbulent motion. It was found that calcite dissolution was controlled not only by the diffusion boundary layer (DBL) at the solid-solution interface, but also by the slow CO2 conversion reaction (CO2 + H2O H+ + HCO3-) in the layer. At high Pco2(Po2>0. 01 atm) ,however .conversion of CO2 occurs mainly in the DBL and therefore becomes rate-limiting. On the other hand, the diffusion boundary layer controls the kinetics of calcite dissolution at low Pco2 (Pco2<0. 01 atm). These findings are explained by use of the DBL model successfully.

关 键 词：CO2-H2O系统 方解石 溶解动力学 二氧化碳 

分 类 号：P578.61[天文地球—矿物学]