CHINESE JOURNAL OF COMPUTATIONAL PHYSICS ›› 2020, Vol. 37 ›› Issue (2): 221-230.DOI: 10.19596/j.cnki.1001-246x.8027

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Adsorption Mechanism of Two Organic Molecules with Different Polarities on Calcite (104) Surface: Density Functional Theory Study

CHAI Rukuan1, LIU Yuetian1, YANG Li2, ZHANG Yixin3, XIN Jing1, MA Jing1   

  1. 1. SKL Petroleum Resources and Prospecting, China University of Petroleum, Beijing 102249, China;
    2. Development Research Department, China National Offshore Oil Corporation Research Institute, Beijing 100028, China;
    3. School of Petroleum and Geological Engineering, University of Oklahoma, Norman, Oklahoma 73019, USA
  • Received:2018-12-18 Revised:2019-01-23 Online:2020-03-25 Published:2020-03-25

Abstract: Density functional theory was employed to explore adsorption mechanism of benzoic acid and toluene molecules on calcite surface, and to analyze influence of polarity on the adsorption. It showed that benzoic acid was tilted adsorbed on CaCO3(104) surface in the form of undissociated molecules and in monodentate mode, while toluene was parallel adsorbed. Geometrical structure of organic molecules changed significantly during the adsorption, in which the deformation of benzoic acid was much greater than that of toluene. Meanwhile, electronic structure of the adsorption system was also changed. During the adsorption of benzoic acid, Ca-O ionic bond and H-O covalent bond were formed. However, there was only weak hydrogen bond between toluene and CaCO3(104) surface. Obviously, adsorption intensity of benzoic acid (polar molecule) on CaCO3(104) surface is greater than that of toluene (non-polar molecule). It provided theoretical support for EOR and mineral flotation engineering.

Key words: density functional theory, CaCO3(104) surface, organic molecules, adsorption mechanism

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