Synthesis, characterization and adsorption optimization of bimetallic La–Zn metal organic framework for removal of 2,4-dichlorophenylacetic acid

Abstract

To eliminate the hazardous pesticide 2,4-dichlorophenylacetic acid (2,4-D) through aqueous solutions, stacked nanorods known as hetero bimetallic organic frameworks (MOFs) of 2-methyl imidazole based on lanthanum and zinc are created. The research's convincing discoveries displayed that La/Zn-MOF is an actual adsorbent for the removal of 2,4-D through aqueous solutions. The La/Zn-MOF was investigated using a variability of techniques, with scanning electron microscope (SEM), powered X-ray diffraction (PXRD), and Brunauer-Emmett-Teller (BET) investigation. La/Zn-MOF has a significant pore capacity of 1.04 cm³/g and a comparatively large surface area of 897.69 m ²/g. Our findings, which are quite intriguing, demonstrate that adsorption behavior is pointedly wedged by variations in pH. A pH 6 dose of 0.02 g was shown to be the optimal setting for the greatest capacity for adsorption. Because adsorption is an endothermic process, temperature variations affect its capability. The adsorption method was fit both isothermally and kinetically using the Langmuir isotherm classical. It was created that the entire process made use of a chemisorption mechanism. Solution pH, temperature, adsorbent dosage, and time were all improved using the Box-Behnken design (BBD) and Response Surface Methodology (RSM). We were able to accurately calculate the values of ΔH ^o, ΔS ^o, and ΔG ^o for 2,4-D by following the guidelines. These results demonstrated the spontaneous and endothermic character of the adsorption procedure employing La/Zn-MOF as an adsorbent. Adsorption-desorption cycles can be carried out up to five times. With the synthesized La/Zn-MOF adsorbent due to its exceptional reusability. Many processes, such π-π interaction, pore filling, H-bonding, or electrostatic contact, were postulated to explain the connection between La/Zn-MOF and 2,4-D after extra research to appreciate well the link was conducted. This is the first study to demonstrate the effectiveness of utilizing La/Zn-MOF as an adsorbent to eliminate 2,4-D from wastewater models. The results display that a pH of 6 is required to achieve the maximal 2,4-D adsorption capability on La/Zn-MOF, which is 307.5 mg/g.

Highlights

• •Synthesis and characterization of La/Zn-MOF.

• •Adsorption of the hazardous herbicide 2,4-D with excellent efficacy.

• •The adsorbent was reusable after five cycles.

• •The adsorption was matched kinetically to a pseudo-second order.

• •Optimization of the results using Box-Behnken design.