Using molecular dynamics simulation method, using Forcite module in Materials Studio2020 software, using COMPASS force field, under the condition of 298 K, The kinetic properties of ions and water molecules in sodium doalkylbenzene sulfonate solutions with densities of 1.016 \(\:\text{g}/{\text{c}\text{m}}^{3}\) , 1.018 \(\:\text{g}/{\text{c}\text{m}}^{3}\) , 1.021 \(\:\text{g}/{\text{c}\text{m}}^{3}\) and 1.025 \(\:\text{g}/{\text{c}\text{m}}^{3}\) were simulated. Different force fields were used for re-simulation to evaluate the sensitivity of model parameters and the stability of micellar structure. Several coupling terms such as Stretch-Stretch and Stretch-Bend-Stretch were evaluated. The experiment found that the density of the solution does not affect the near-range hydration structure of Na+, but it has a certain influence on the near-range hydration structure of SDB-. In the aqueous solution of sodium dodecylbenzene sulfonate, sodium dodecylbenzene sulfonate mainly exists in ionic form in water and spontaneously forms micelles with a stable micelle system. In addition, as the density of the solution decreases, the diffusion capabilities of water molecules, Na + and SDB- all increase. In the SDBS solution, the flexibility of the SDB- chain reaches its best approximately when the solution density is 1.025 \(\:\text{g}/{\text{c}\text{m}}^{3}\) . Understanding the microscopic properties of SDBS solution provides a theoretical basis for effectively removing SDBS from aqueous solutions.
