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NEW CORRELATION METHOD OF LIQUlD-PHASE ADSORPTION EQUILIBRIUM BY FRONTIER ORBITAL THEORY

前沿轨道理论液相吸附平衡关联新方法

基本信息

批准号：
04650853
负责人：
TAMON Hajime
金额：
$ 1.28万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1992
资助国家：
日本
起止时间：
1992 至 1993
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-04650853/
关键词：
Adsorption equilibrium in liquid phase Frontier orbital theory Semi-empirical molecular orbital calculation Activated carbon Synthetic adsorbent Adsorptive interaction Hythteresis of adsorption and desorption Surface modification

项目摘要

1.Data-Base for Liquid Phase AdsorptionThe experimental results showed that the amounts of the aromatic hydrocarbons adsorbed were large, whose substituting groups were electron-donating. On the other hand, it was found that the amounts of the aromatic hydrocarbons with electron-attracting groups adsorbed were small. Aromatic compounds with electron donation groups showed the hysteresis of adsorption and desorption in the liquid phase on activated carbon. On the other hand, aromatic compound with electron attracting groups showed no hysteresis. No hysteresis was detected for all adsorbates on the synthetic adsorbents.2.Correlation of Affinity Coefficient in Liquid-Phase AdsorptionThe adsorptive interaction of hydrocarbons in aqueous solution on the activated carbon and the synthetic adsorbents was regarded as a mixing of HOMO and LUMO.The method to estimate the adsorption energy was proposed according to the frontier orbital theory and the semi-empirical molecular orbital calculation. It was found that the charge transfer interaction plays an important role in liquid-phase adsorption and the affinity coefficient determined by D-R equation can be correlated by the ratio of adsorption energy of some adsorbate to that of the reference adsorbent. The prediction method of adsorption equilibrium was proposed.3.Effect of Surface Modification on Adsorption and Desorption Characteristics in Liquid-PhaseWhen activated carbon and graphite were oxidized, the amount adsorbed of aromatic compounds were decreased. The desorption characteristic, however, was improved by wet oxidation. The influence of surface functional groups of the carbon on adsorption and desorption characteristics was explained taking into account the change of adsorption energy by oxidation. It was deducted that the surface modification with electron-attracting groups is useful to increase the amount adsorbed on synthetic adsorbents.

1.液相吸附数据库实验结果表明，芳烃类化合物的吸附量较大，其取代基团为给电子基。另一方面，发现吸附有吸电子基团的芳香烃的量很少。含给电子基的芳香族化合物在活性炭液相中表现出吸附和脱附的滞后现象。另一方面，含吸电子基团的芳香族化合物没有表现出滞后现象。2.液相吸附中亲和系数的相关性将水溶液中的烃类化合物在活性碳和合成吸附剂上的吸附作用视为HOMO和LUMO的混合，根据前线轨道理论和半经验分子轨道计算，提出了估算吸附能的方法。结果表明，电荷转移相互作用在液相吸附中起着重要作用，D-R方程所确定的亲和系数可用某些吸附物的吸附能与参比吸附剂的吸附能之比关联。提出了吸附平衡的预测方法。3.表面改性对液相吸附与脱附特性的影响当活性碳和石墨被氧化时，芳香族化合物的吸附量减少。然而，湿式氧化改善了脱附特性。考虑到氧化过程中吸附能的变化，解释了碳表面官能团对吸附和脱附特性的影响。结果表明，用吸电子基团进行表面修饰有利于提高合成吸附剂的吸附量。