Tuned Iron-Manganese MOFs Boost Tetracycline Removal from Water

A bimetallic metal-organic framework tuned to a specific iron-to-manganese ratio has shown the strongest tetracycline hydrochloride adsorption among a family of related materials, according to a study published in the Journal of Materials Science. The research, led by Gang Yang and colleagues, describes how varying the nominal Fe/Mn precursor ratio during synthesis reshapes the crystallization behavior, pore structure, and metal-site environment of the frameworks, ultimately identifying Fe1Mn5-MOF as the best performer with an equilibrium adsorption capacity of 338.96 milligrams per gram at 318 kelvin.

Tetracycline hydrochloride is a growing concern in water pollution control because of its environmental persistence and its potential to promote antibiotic resistance. Conventional monometallic MOFs often struggle with adsorption because they expose too few active sites. The team’s strategy was to regulate both pore accessibility and the chemical nature of metal sites simultaneously rather than maximizing surface area alone. Notably, Fe1Mn5-MOF did not have the highest specific surface area among the bimetallic samples tested, yet it delivered the highest measured capacity, pointing to a combined influence of pore characteristics and active-site properties rather than any single structural metric.

Characterization before and after adsorption, using FTIR, BET, and XPS techniques, together with density functional theory calculations, suggested that tetracycline uptake involved several cooperating mechanisms: adsorption within pores, pi-pi interactions, hydrogen bonding, and coordination between the antibiotic and Fe/Mn-O or Fe/Mn-N sites. Fe1Mn5-MOF combined favorable pore accessibility with an abundance of acidic sites, conditions the authors link to its superior performance.

The study is a laboratory-scale materials investigation, and the reported capacity applies to equilibrium adsorption under the tested conditions rather than to treatment of real water systems. Even so, the work offers mechanistic insight into how composition-dependent regulation of pore structure and active sites can be engineered in bimetallic MOFs, an approach the authors suggest could guide the design of adsorbents for antibiotic-contaminated water.

Subject of Research: Bimetallic Fe/Mn metal-organic frameworks engineered for tetracycline hydrochloride adsorption from water

Article Title: Regulated synergistic optimization of pore structure and active sites in bimetallic MOFs for tetracycline hydrochloride adsorption: mechanism and insights

Article References: Yang, G., Zhang, Z., Chen, Y., Gao, M., Lu, Y., Niu, H., Zhao, Y., & Chen, Y. (2026). Regulated synergistic optimization of pore structure and active sites in bimetallic MOFs for tetracycline hydrochloride adsorption: mechanism and insights. Journal of Materials Science. https://doi.org/10.1007/s10853-026-13993-1

Image Credits: AI Generated

DOI: 10.1007/s10853-026-13993-1

Keywords: metal-organic frameworks, tetracycline hydrochloride, adsorption, bimetallic MOFs, iron-manganese, water pollution, antibiotic resistance, pore structure, active sites, DFT calculations, Regulated, synergistic