With UiO-66 metal organic framework as the adsorbent, the influences of factors such as time, pH value, temperature on the adsorption were studied. The results showed that the adsorption effect was best at pH=4.0 for the adsorption system and the adsorption equilibrium time was 24 h. The equilibrium adsorption capacity increased with the increasing temperature and the optimal temperature should be controlled at 30℃. The adsorption of 2,4-D on UiO-66 followed Langmuir isotherm model and the adsorption kinetics could be better described by pseudo-second-order model. The intraparticle diffusion process was the rate-controlling step for adsorption processes. The results of thermodynamic calculations showed that ΔG<0, ΔH>0, ΔS>0. So the adsorption was a spontaneous, endothermic chemical process with increased randomness. The main interaction forces of adsorption were chemical bonding force and electrostatic interactions force. Results of the study suggested that UiO-66 had the potential ability for 2,4-D removal from wastewater.
Keywords: 2,4-D; UiO-66; adsorption kinetics; adsorption performance; adsorption thermodynamics.