Synthesis and characterization of novel La/Rb bimetal-organic frameworks for efficient adsorption of 2,4-Dichlorophenoxyacetic acid from aqueous solutions: Adsorption isotherm, kinetics, optimization via Box-Behnken design, and DFT calculations

This work investigated the adsorption properties of lanthanum/rubidium bimetal-organic frameworks (La/RbMOF) with the goal of removing the hazardous herbicide 2,4-Dichlorophenoxyacetic acid (2,4-D) from aqueous solutions. SEM, TEM, PXRD, XPS, FT-IR, and BET experiments were employed to extensively analyze the substance's properties. A significant surface area of 1560.91 m(2)/g was observed in the data, suggesting a prospective for a high adsorption capability. A positive charge beyond the point of zero charge (5.14) and a negative charge after it were shown to have an impact on the adsorption behavior, according to the surface charge analysis. Through batch experiments, the study investigated how pH affected adsorption equilibrium and offered insights into the environmental variables influencing the adsorption procedure. At a pH of 4, the maximal 2,4-D adsorption onto La/Rb-MOF was found to reach 452.6 mg.g(-1). The structure, reactivity and 2,4-D electrical properties were determined using density functional theory (DFT). DFT indicates that there is respectable agreement between the location of the electrophilic and nucleophilic violence sites and the molecular orbitals (HOMO and LUMO) and MEP data. The kinetics of the reaction were elucidated using pseudo-second-order kinetic models. The Langmuir isotherm model, which consistently showed a chemisorption procedure, demonstrated to be an accurate forecaster of the adsorption mechanism. Interestingly, the predicted thermodynamic characteristics of our investigation showed that the entire adsorption-desorption procedure was endothermic and spontaneous in nature (Delta H degrees), (Delta S degrees), and (Delta G degrees) while using the adsorbent La/Rb-MOF. La/Rb-MOF and 2,4-dichlorophenylacetic acid (2,4-D) were found to interact by a mechanism that took into account elements such as electrostatic contact, it-it interaction, and pore filling. Additional investigation evaluated the adsorbent's capacity for regeneration while evaluating the removal efficacy and its ability to function continuously for more than eight cycles. The Box-Behnken Design was active in order to optimize the results of adsorption. This analysis highlights how La/Rb-MOF can be used to handle real-world wastewater treatment difficulties in a sustainable and practical manner.