Establishing Linear Free Energy Relationships for the Chemical Reactivity of Metal Ions in Aqueous Solution and on Mineral Surface

• Main Authors: Tai-Hong Lin, 林泰宏
• Other Authors: Chia-Ming Chang
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/21445296831946914578

碩士 === 國立中興大學 === 土壤環境科學系所 === 96 === Basic reactions of metal ions such as the hydration, hydrolysis, precipitation, diffusion, and redox are important in the aqueous solution. Furthermore, the adsorption, ionic exchange reactions occur on the soil mineral surface system. Regarding chemical reactions as the effect between molecule and molecular, however also have to consider effectively colliding and the main reaction position. Therefore need to combine the global with local approach in discussing chemical reactions are most suitable. This thesis was achieved by the conceptual density functional theory to calculate the hydrated metal ion model. Differentiating the chemical reaction relations for the global and local two major parts, and both are again subdivided into charge controlled and orbital controlled two parts, from this could obtain the forecast parameters. The global charge controlled is by the atomic charge (Z), namely the valence number, and the orbital controlled is by chemical hardness and global interaction (ΔEint). The local charge controlled is potential (ρ+、ρ-), and orbital controlled is by the Mulliken population analysis to obtain Fukui function(f+、f-), and further could obtain local soft(s+、s-) by the Fukui function (s+, s-). Above parameters will carry on the multi-regression analysis with literature experiment values of the hydration, hydrolysis, diffusion, precipitation, redox, adsorption, cation exchange reactions, and finally inspect the forecast results by DFT-based linear free-energy relationship (DFT-based LFER). Reactions of the hydrated metal ions in the aqueous solution are mainly effected by the global parameters, in other words the metal valence and metal itself hard and soft acids and bases'' properties. The redox is mainly decided to the metal itself chemical hardness. Besides the adsorption, cation exchange reactions occur on the soil mineral surface system. Adsorption is decided by all the local parameters, has nothing to do with the global parameters, need to consider from the coulomb interaction correlation and local soft of hydrated metal ions, especially more important by the coulomb static electricity interaction. The cation exchange coefficient forecast result is also good, and the difference of DZ and MB mainly is due to the different basis sets. However it still was worthy of observing at the cation exchange coefficient effected by the hydrated metal ion itself chemical hardness and the coulomb static electricity interaction action influence between the metal ions and adsorbent. Whole forecast results are extremely good, and supported by the theoretical chemistry foundation basis, unifying the global and local concept in the chemical reactions successfully explain the basic reactions of metal ions in the aqueous solution or on the mineral surface system.