Adsorption behaviors and mechanisms by theoretical study of herbicide 2,4,5-Trichlorophenoxyacetic on activated carbon as a new biosorbent material

Background: Adsorption remediation is a low-energy water treatment technology based on removing different types of pollutants using the adsorption properties of a biosorbent. However, the biosorption of the pesticide 2,4,5-Trichlorophenoxyacetic on a plant named Ritama-Monosperma (L.) Boiss carbonized and activated by phosphoric acid as a new potential modern and eco-friendly biosorbent is the subject of this work. Methods: The characteristics of the biosorbent are then determined utilizing several structural and textural characterization techniques such as XRD, FTIR, SEM/EDX, pHzpc, and Boehm titration. Batch adsorption tests were performed to investigate the impact of various parameters. However, the Freundlich, Languemir, Temkin, and Dubinin-Radushkevich models were employed to examine the experimental isotherm data. The density functional theory (DFT) modeling of 2,4,5-Trichlorophenoxyacetic has allowed us to discover the origin of the reactivity. Significant findings: According to biosorption kinetic data, the elimination of 2,4,5-Trichlorophenoxyacetic followed a pseudo-second-order response with a maximum adsorption capacity of 24.17 mg/g. The generalized isotherms demonstrated that the Freundlich isotherm best fitted the equilibrium data. The Thermodynamic study shows that pesticide biosorption is exothermic, spontaneous, and represents a decrease in randomness at the adsorbent-adsorbate interface, which is regulated by physisorption and happens as a result of electrostatic interactions, between the positively charged carbon surface at pH below 2.5, and the most nucleophilic centers C2, C5, C15, according to theoretical calculations, and pHzpc analysis.

Automated summary

This study investigates the adsorption properties of the pesticide 2,4,5-Trichlorophenoxyacetic on a phosphoric acid activated biosorbent derived from Ritama-Monosperma (L.) Boiss plant. Various characterization techniques were used to determine the structural and textural properties of the biosorbent. Batch adsorption tests were performed, and several models were employed to analyze the experimental data. DFT modeling revealed the reactivity of the pesticide. The kinetics of adsorption followed a pseudo-second-order response, and the Freundlich isotherm best described the equilibrium data. Thermodynamic analysis showed that the biosorption process is exothermic and spontaneous, with a decrease in randomness at the adsorbent-adsorbate interface.