Study on the Application of Cucurbit[6]uril as a Nanoporous Adsorbent for the Removal of 2,4-Dinitrophenol from Wastewaters

In the present study, cucurbit[6]uril was used as a nonporous adsorbent for the removal of 2,4-dinitrophenol from aqueous solutions. The experiments were carried out in a batch system to optimize operation variables such as pH of solution, contact time, adsorbent dose and salt concentration. Langmuir, Freundlich and Tempkin isotherms were applied for the explanation of experimental data. The high removal yield was achieved at the real pH, 0.02 g of adsorbent dose and 10 min of contact time. The equilibrium adsorption was best described by the Langmuir isotherm model. The maximum monolayer adsorption capacity was found at 29.85 mg g-1 for 2,4-dinitrophenol at 25 °C. The kinetics study showed that the adsorption process could be described by pseudo-second order rate equation, and equilibrium was achieved after 10 min. The thermodynamic parameters indicated that the adsorption of 2,4-dinitrophenol on the cucurbit[6]uril is an endothermic and spontaneous process. The results of the present study confirm the applicability of small amount of this adsorbent for efficient removal of 2,4-dinitrophenol from wastewater samples in short reasonable time.