adsorptive Removal of Sunset Yellow from Aqueous Solutions with Magnetic Iron Oxide Nanoparticles

Sunset yellow (SY) is an azo dye, which can cause damage to liver function and children’s intelligence [1]. On the other hand, magnetic nanoparticle-based adsorbent have attracted much attention as excellent adsorption materials due to their large specific surface area, easy surface functionalization and the fact that magnetic systems can be easily separated and collected by applying an external magnetic field [2]. In this research, the potential of magnetic nanoparticle for removal of sunset yellow dyes from aqueous solutions was investigated. Characterization of the prepared nanoparticles was accomplished by FT-IR, SEM, XRD and VSM techniques. The SEM image of as-prepared MNPs represents plenty of spherical particles, with the average size smaller than 200 nm, that they were used in this study. The recorded VSM showed the magnetization curve was S-like, exhibiting superparamagnetic behavior with no coercivity and hysteresis. Batch adsorption experiments were conducted using synthetic solutions and the effects of initial dye concentration, initial pH of solution, adsorbent dose and contact times were studied. From the results, the removal process reached high percentage within 5 min, and the adsorption efficiency increased with the enhancement of initial dye concentration, adsorbent dosage, but decreased with the enhancement of solution pH. Removal percent of SY reached to 93% by increasing adsorbent dosage and the maximal adsorption capacity of SY occurs in the neutral pH range (5-7). Moreover, the adsorption isotherms could be well-defined with the Langmuir isotherm model instead of the Freundlich isotherm model. The obtained results confirmed that Langmuir isotherm model gives the best fit with the highest R2 value ( 0.98) compared to the other models. The obtained results indicated that synthesized magnetic nanoparticles could be utilized as efficient, magnetically separable dyes from the real sample.