Integrating experimental and computational tools for adsorptive removal of Dicamba using UiO-66(Zr)-impregnated cholinium alanate ionic liquid

Abstract

Dicamba herbicide contamination in water sources poses significant environmental risks, necessitating effective removal strategies. This study investigates the development of hybrid adsorbents by incorporating [Ch][Ala] ionic liquid into UiO-66(Zr) metal-organic frameworks to enhance adsorption performance. The hybrid materials were synthesized and characterized using NMR, XRD, FESEM, BET, FTIR, and TGA, confirming structural stability and successful incorporation of [Ch][Ala]. Adsorption experiments, optimized using response surface methodology (RSM) and machine learning, demonstrated that the 5 % [Ch][Ala]-loaded hybrid achieved a maximum Dicamba removal efficiency of 99.51 %. The adsorption followed the pseudo-second-order model, indicating the chemisorption is the primary control mechanism in the adsorption process. Isotherm studies revealed that the adsorption data fit well with the Langmuir isotherm model, indicating monolayer adsorption on homogeneous surfaces with the maximum adsorption capacities of 72.31 and 78.02 mg/g for pristine and UiO-66(Zr)/[Ch][Ala]@5 %, respectively. The adsorption thermodynamics confirmed the feasibility of the reaction and spontaneity of the adsorption process. The enhancement in adsorption capacity of Dicamba can be attributed to functional groups introduced by [Ch][Ala], through π–π and hydrogen bonding which enhance interactions between the adsorbate and hybrid MOF adsorbent.