Investigating the wetting effectiveness of surfactant blends on anthracite coal dust: combined experimental and molecular simulation approaches

Abstract

Abstract Conventional water spraying methods often prove inadequate due to the poor wettability of these coal dust particles. To address this, the present study introduces a comprehensive strategy that integrates molecular dynamics (MD) simulations with laboratory experiments to systematically explore the, wetting performance of surfactant composite systems and develop high-efficiency wetting agents suitable for anthracite dust in the Yangquan mining area.Characterization of the anthracite samples using Fourier Transform Infrared Spectroscopy (FTIR) and proximate and ultimate analysis revealed a high prevalence of hydrophobic surface groups. To counter this, MD simulations employing a Spiro anthracite model were conducted to analyze coal-water and coal-surfactant-water systems. Key simulation metrics-including non-bonded interaction energy, mean square displacement (MSD), electrostatic potential (ESP) distribution, and relative concentration demonstrated that selected surfactants significantly enhance water interaction and reduce coal surface hydrophobicity.Sodium dodecyl sulfate (SDS), sodium dodecylbenzene sulfonate (SDBS), and sodium alcohol ether sulfate (AES) were identified as the most effective monomeric surfactants based on simulation data. These findings were further validated through contact angle measurements, surface tension analysis, and penetration tests. Compared to a surfactant-free system, the selected surfactants significantly enhanced wetting performance, demonstrating a 62.3% reduction in contact angle, a 57.15% decrease in surface tension, and a 4.4-fold increase in penetration rate-confirming their practical efficacy in improving wetting behavior.Single-factor tests were carried out to verify the wetting capacity of individual surfactants and measure their critical micelle concentration (CMC). Combined with orthogonal tests, the compound formula was further optimized, and the optimal proportion was confirmed as 0.25 wt% SDS + 0.20 wt% SDBS + 0.35 wt% AES. This optimized surfactant compound exhibited desirable properties, including weak alkalinity, excellent fluidity, low corrosiveness, and strong environmental compatibility, along with significantly enhanced wetting of anthracite dust.