Applying molecular docking in screening and analyzing ester-based collectors for low-rank coal flotation: A novel approach

Abstract

Ester-based hydrocarbon oils, possessing hydrophobic, dispersant, and eco-friendly properties have gained the attention of researchers as flotation collectors for low-rank coal flotation. This study innovatively applied molecular docking technology typically used in the biomedical field to investigate ester-based collectors for low-rank coal flotation and analyzed the feasibility of molecular docking in the selection of flotation reagents. The structural characteristics of low-rank coal were analyzed using scanning electron microscopy–energy-dispersive spectroscopy, X-ray photoelectron spectroscopy, nuclear magnetic resonance spectroscopy, transmission electron microscopy, and a 3D macromolecular structure of low-rank coal was constructed. A holistic docking approach was applied to score and analyze methyl alkylate and caprylate ester series flotation collectors. The methyl alkylate series collectors exhibited effectiveness in the order of methyl caprylate < methyl pelargonate < methyl caprate < methyl undecanoate < methyl laurate < methyl tridecrate, and the caprylate ester series collectors displayed effectiveness in the order of methyl caprylate < ethyl caprylate < propyl caprylate < butyl caprylate. These results are consistent with the subsequent analysis of the binding configurations and surface adsorption of the collectors, indicating that a collector with a high score has a tight adsorption configuration and exhibits good surface hydrophobic modification. Practical flotation experiments with methyl alkylate series and caprylate ester series collectors showed that, for both types of collectors, the combustible recovery of separated coal increased with increasing score, and a positive correlation was observed between flotation recoverability and the scoring value. This result suggests that the molecular docking method can be used to evaluate the performance of coal flotation collectors, providing a new approach for computer-aided coal flotation reagent screening.