Development of Metal–Organic Frameworks (MOFs) for Gas Storage and Environmental Remediation

Abstract

Metal–organic frameworks (MOFs) have emerged as one of the most transformative classes of porous materials in materials science and environmental engineering. Defined by their crystalline networks of metal nodes bridged by multidentate organic linkers, MOFs possess unparalleled surface areas (up to 7000 m² g⁻¹), highly tuneable pore geometries, and diverse chemical functionalities. These attributes make them ideally suited for gas storage applications—including CO₂ capture, H₂ storage, and CH₄ uptake—as well as for the adsorptive and catalytic removal of environmental contaminants from water and air. Despite their remarkable properties, the practical deployment of MOFs faces significant challenges: limited chemical and hydrolytic stability under real environmental conditions, scalable and cost-effective synthesis, selectivity in complex multi-pollutant matrices, and performance retention across multiple regeneration cycles. Furthermore, concerns over metal ion leaching and the toxicological profile of certain framework components must be addressed before widespread application in water treatment is feasible. This study reports the solvothermal synthesis and systematic characterisation of six MOF platforms—HKUST-1, MIL-101(Cr), ZIF-8, UiO-66, MIL-53(Al/Fe), and MOF-5—and their evaluation for (i) CO₂, CH₄, and H₂ gas uptake, (ii) adsorptive removal of heavy metals (Pb²⁺, Cd²⁺), organic dyes, pharmaceutical pollutants, and emerging contaminants, and (iii) advanced oxidation processes (photo-Fenton, Fenton-like, persulfate activation) for recalcitrant pollutant degradation. Materials were characterised by PXRD, FTIR, N₂ adsorption–desorption (BET), TGA, and SEM/TEM. HKUST-1 achieved a CO₂ uptake of 280 cm³ g⁻¹ at 25 bar, while MIL-101(Cr) exhibited the highest BET surface area (3780 m² g⁻¹) and superior dye adsorption capacity (512.3 mg g⁻¹ for methylene blue). Fe-MIL-53 driven photo-Fenton degradation achieved 97.3% removal of bisphenol F within 60 minutes. All MOFs retained greater than 90% of their initial performance across five consecutive regeneration cycles. The results collectively demonstrate that rationally designed MOFs can provide high-performance, multifunctional solutions for gas storage and environmental remediation, with performance parameters that are competitive with or superior to conventional adsorbents and catalysts.