Zirconium-ferrite nanoparticles for efficient adsorptive removal of methylene blue from aqueous medium

This study investigated the use of zirconium–ferrite nanoparticles (ZF-NPs) as an efficient adsorbent for the removal of methylene blue (MB) from aqueous solutions. The nanoparticles were created using a co-precipitation method and were previously characterized as mesoporous particles with a charge point of zero of roughly 3.9, a very high surface area, and a small particle size (16–20 nm), all of which combined to offer a lot of reactive and easily accessible adsorption sites. The effects of temperature (288–333 K), initial dye concentration (10–50 mg/L), pH (2–8), adsorbent dosage (0.05–0.30 g), and contact time (10–80 min) on MB uptake were assessed using batch adsorption experiments. The Langmuir isotherm revealed a maximal monolayer adsorption capacity of 238.10 mg/g at ideal circumstances of 0.2 g ZF-NPs, pH 4.0, contact period of 60 min, and initial MB concentration of 10 mg/L. Chemisorption-dominated uptake on energetically heterogeneous surface sites was indicated by kinetic analysis, which demonstrated that the adsorption process followed the pseudo-second-order model (R² = 0.999) and was well described by the Elovich equation. Thermodynamic parameters (negative ΔG°, ΔH° ≈ −41.15 kJ/mol, and ΔS° ≈ −49.30 J/mol.K) confirmed that MB adsorption on ZF-NPs was spontaneous and exothermic with reduced randomness at the solid–solution interface. The synthesized ZF-NPs demonstrated a noticeably higher adsorption capacity while maintaining magnetic separability when compared to a variety of documented adsorbents for MB, such as zeolite, biomass-derived carbons, polymer-based hydrogels, and other oxide materials. Overall, this work showed the potential of zirconium–ferrite nanoparticles as a next-generation adsorbent for dye-contaminated wastewater by extending their use to MB removal for the first time and exhibiting a unique combination of ultra-high surface area, strong chemisorptive interaction, and simple magnetic recovery. This clearly offered a performance and handling advantage for water treatment.