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

MIL-125(Ti)@Fe metal–organic framework as a dual-functional catalyst for adsorption and Fenton-like photodegradation of azo dyes in textile effluents

Felycia Edi Soetaredjo, Suryadi Ismadji, Shella Permatasari Santoso, Jessica Chrisanta Soegianto, Jindrayani Nyoo Putro, Darwin Kurniawan, Michael Suryananda Ismadji, Alfin Kurniawan, and Jenyfer Sugianto

Department of Chemical Engineering, Widya Mandala Surabaya Catholic University, Surabaya, Indonesia

E-mail: felyciae@yahoo.com

Received: 5 February 2026  Accepted: 19 May 2026

Abstract:

A bifunctional Fe-modified titanium metal–organic framework, MIL-125(Ti)@Fe, was rationally designed to integrate adsorption preconcentration and photo-Fenton degradation for efficient removal of anionic azo dyes from textile wastewater. Structural characterization confirmed that low-level Fe incorporation preserves the MIL-125(Ti) framework while narrowing the band gap from 3.20 to 2.28 eV, thereby extending light absorption into the visible region. Compared with pristine MIL-125(Ti), MIL-125(Ti)@Fe exhibited substantially enhanced adsorption capacities toward CI Direct Blue 1 and CI Direct Yellow 4, as well as near-complete degradation of the residual dye after adsorption equilibrium under UV/visible irradiation in the presence of H₂O₂. Kinetic analysis revealed pseudo-first-order degradation behavior with thermally assisted reaction rates. The synergistic enhancement arises from adsorption preconcentration coupled with Fe-assisted H₂O₂ activation, as supported by radical trapping experiments showing an •OH-dominated degradation pathway. Potential interfacial electron-transfer effects are discussed as a plausible contribution rather than as directly confirmed charge-separation evidence. The catalyst retained over 90% of its activity after five consecutive cycles, demonstrating excellent structural robustness. This work establishes a design principle for Fe-assisted Ti-MOF platforms that couple adsorption and photo-Fenton catalysis, offering a sustainable and reusable strategy for advanced wastewater treatment. Unlike conventional Fe oxide-loaded MOFs or photocatalysis-focused Ti-MOF systems, the present low-level Fe-modified MIL-125(Ti) couples high adsorption capacity, •OH-dominated photo-Fenton degradation, low Fe leaching, and stable recyclability within a single framework-preserved material.

Keywords: Photocatalyst; Photodegradation; Recyclability; Green adsorbent

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-026-05084-x

Chemical Papers 80 (10) 11685–11700 (2026)