煤气化灰渣渗滤液中重金属离子吸附去除的分子动力学模拟

Heavy metal ions in coal gasification ash pose significant risks to the environment and human health, necessitating the urgent development of efficient remediation methods. Carbon nanotubes (CNTs) exhibit advantageous properties such as large specific surface area, high stability, and superior adsorption performance, which can be further enhanced through modification with specific functional groups. In this study, molecular dynamics simulations were employed to investigate the adsorption behaviors of carboxyl-functionalized single-walled carbon nanotubes (CNT —COO-) toward heavy metal ions (Cu2+ and Cd2+) present in water contaminated by coal gasification ash. Simulation results indicated that adding a sufficient amount of CNTs simultaneously provided favorable overall removal efficiency for heavy metal ions in mixed-ion systems. To better understand the adsorption mechanisms, the effects of varying functionalization coverage and solution temperature on parameters such as radial distribution number density and mean square displacement were analyzed. It was found that CNTs functionalized with 25% carboxyl groups demonstrated stable adsorption performance for heavy metal ions at an ionic concentration of 0.1 mol/L, exhibiting superior adsorption affinity toward Cu2+ ions in mixed solutions. Additionally, the adsorption capacity of CNT—COOincreased with higher initial ion concentrations, though the relative proportion of adsorbed ions gradually decreased. The findings from this study provide valuable insights into the application of functionalized CNTs for the adsorption and removal of heavy metal ions, laying a theoretical foundation for further modifications of carbon-based adsorbents.