Bimetallic MOFs for the effective removal of organic contaminants: Dyes and antibiotics

We report the successful solvothermal synthesis of Iron-Nickel bimetallic MOFs (F:N@BTC) as a heterogeneous catalyst without high-temperature annealing. F:N@BTC demonstrated superior catalytic activity in the removal of Organic Contaminants (OCs) attributed to the synergistic effects of two metals (Fe-Ni), high specific surface area (673 m 2 g −1 ), and mesoporous structure. The negatively charged surface of F:N@BTC (zeta potential ∼-30 mV) enhances adsorption, particularly for the cationic OCs. The adsorption capacity (q e , mg g −1 ) of F:N@BTC for OCs follows the order: Toluidine Blue (TB, 962) > Rhodamine B (RB, 842) > Ciprofloxacin (CF, 808) > Nalidixic acid (NA, 616) > Rose Bengal (RoB, 595) within 2 hours without using reducing agent. This result indicates the order of higher adsorption capacity towards cationic to anionic surface charge of the OCs. Comparative studies confirm F:N@BTC’s superiority over monometallic analogs (F@BTC, N@BTC). Kinetic analysis reveals the adsorption of OCs on F:N@BTC followed pseudo-second-order kinetics indicating chemisorption with intraparticle diffusion contributing co-operatively. This work highlights the potential of F:N@BTC MOFs as an efficient adsorbent for the wastewater treatment across diverse Organic Contaminants. • Bimetallic Fe-Ni MOFs (F:N@BTC) prepared via solvothermal route without high-temperature annealing. • Remarkable removal efficiency for cationic dyes. • The adsorption capacity (cationic > amphoteric > zwitter ionic > neutral > anionic) directly correlates with contaminant surface charge. • The synergistic effect and high surface area (673 m² g⁻¹) of F:N@BTC boost performance over monometallic MOFs. • Adsorption follows pseudo-second-order kinetics , suggesting chemisorption with intraparticle diffusion.