Molecular model construction and study of surfactant wetting of carbon black

Abstract

An experiment and simulation study on the carbon black adsorption of surfactant were conducted to explore the adsorption mechanism to assist in the prediction and prevention of dust accidents. Elemental analysis, 13C solid nuclear magnetic resonance (13C-NMR), and X-ray photoelectron spectroscopy (XPS) were used to construct the model of the carbon black. Molecular dynamics (MD) and molecular mechanics (MM) were used to optimize the model of the carbon black, and the periodic boundary condition was added using the relationship between energy and density. The adsorption behavior of surfactants on the surface of carbon black molecules was studied using molecular dynamics simulation. In the molecular model of carbon black aromatic compounds mainly exist in the form of the benzene ring; aliphatic compounds mainly exist in the form of aliphatic side chains and cycloalkanes; oxygen atoms exist as carbonyl group, ether group, and carboxyl group; and nitrogen atoms exist as pyridine and pyrrole. The final density of the carbon black molecule model is 1.5 g/cm3. The molecular simulation results show that the nonionic surfactants have a better wetting effect on carbon black. Interaction between carbon black molecules and surfactants is caused by electrostatic force and van der Waals force, increasing the number of water molecules adsorbed by carbon black. The simulated adsorption results have a good predictive effect on the modification, removal, and dust control of carbon black.