ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Ti-MOF encapsulated in chitosan/epichlorohydrin for the removal of Diuron herbicide: adsorption models, DFT calculations and optimization by Box-Behnken design

Aisha Hossan

Department of Chemistry, Faculty of Science, King Khalid University, Abha, Saudi Arabia

E-mail: ahossan@kku.edu.sa

Received: 27 August 2025  Accepted: 6 October 2025

Abstract:

The effective creation of Ti-MOF@Chitosan/Epichlorohydrin beads (TCEH) was achieved by encapsulating a titanium metal–organic framework within chitosan and subsequently crosslinking it with epichlorohydrin. The performance of this adsorbent material was assessed through several analytical practices, including FT-IR, XRD, SEM, XPS, and BET surface area measurement. The influence of aspects such as temperature, initial concentration, adsorbent dosage, and pH on the adsorption of Diuron onto TCEH was analyzed. It was discovered that a pH of 8 and an adsorbent dosage of 0.02 g were the ideal parameters for reaching a high adsorption capacity of 441.8 mg. The findings fit the Langmuir model, according to an analysis of adsorption isotherm models, whereas a pseudo-second-order model best explained the kinetics. The adsorption process was suggested to occur mainly through chemisorption, characterized by an energy requirement of 28.6 kJ mol^–1. Thermodynamic analysis further indicated that the positive ΔH° and negative ΔG° values confirm that the adsorption is both spontaneous and endothermic. Additionally, several complex mechanisms contributing to the adsorption were identified, including π–π bonding, chemisorption, electrostatic interactions, hydrogen bonding, and the pore-filling effect within the TCEH beads. Techniques like Response Surface Methodology and Box-Behnken design (BBD) were used to maximize the adsorption results. Additionally, Diuron’s electrical characteristics, reactivity, and structure were examined using density functional theory (DFT).

Keywords: Chitosan; Epichlorohydrin crosslinking; Ti-MOF; Box-Behnken design

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-025-04440-7

Chemical Papers 80 (1) 959–984 (2026)