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

1.液相吸附数据库实验结果表明，芳香烃吸附量大，其取代基为供电子基团。另一方面，具有电子吸引基团的芳烃吸附量较少。具有给电子基团的芳香族化合物在液相中对活性炭的吸附和解吸具有滞后性。而含有电子吸引基团的芳香族化合物则没有迟滞现象。合成吸附剂上的所有吸附均未检测到滞后现象。液相吸附过程中亲和系数的相关性将水溶液中烃类在活性炭和合成吸附剂上的吸附相互作用视为HOMO和LUMO的混合。根据前沿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。发现电荷转移相互作用在液相吸附中起重要作用，用D-R方程确定的亲和系数可以用吸附能与参比吸附剂的吸附能之比进行关联。提出了吸附平衡的预测方法。表面改性对液相吸附和解吸特性的影响活性炭和石墨氧化后，芳香族化合物的吸附量减少。湿式氧化改善了其解吸特性。考虑氧化作用下吸附能的变化，解释了碳表面官能团对吸附和解吸特性的影响。结果表明，利用电子吸引基团进行表面改性有助于提高合成吸附剂的吸附量。

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.