Synthesis, characterization and adsorption properties of a novel biomagnetic composite for the removal of Congo red from aqueous medium

• Published in: Journal of molecular liquids 2015-11, Vol.211, p.515-526
• Main Author: Akkaya Sayğılı, Gülbahar
• Format: Article
• Language: English
• Subjects: Congo red; Dye adsorption; Magnetic composite; MnFe2O4 nanoparticles; Pomegranate waste
• ISSN: 0167-7322; 1873-3166
• DOI: 10.1016/j.molliq.2015.07.048

A novel biomagnetic composite (MnFe2O4/PW) was synthesized and used for the removal of Congo red (CR) from aqueous solutions. Adsorption of CR on the composite adsorbent was studied as a function of time (5–300min), initial CR concentration (100–200mg/L), composite dose (0.05–0.1g), pH (6–10), and temperature (25–55°C). The properties of the biomagnetic composite were measured by BET, SEM, SEM–EDX, FTIR, XRD, and VSM techniques. The kinetics and isotherm studies were carried out under optimum removal conditions of CR by MnFe2O4/PW. The kinetics and equilibrium data fitted to the pseudo-first-order kinetics and Langmuir isotherm models. Using CR as model pollutant, the prepared composite adsorbent showed good adsorption capacity of 86.96mg/g. Thermodynamic analysis showed that the adsorption was favorable, spontaneous and endothermic. The adsorbent could be regenerated using 50% of ethanol–water solution, remaining 87.36% of its original capacity after the first regeneration cycle and reaching 65.68% of the original capacity after the fifth cycle. This study shows that the synthesized biomagnetic composite could be utilized as an efficient and magnetically separable adsorbent for the dye removal applications. •Magnetically separable MnFe2O4–pomegranate waste composite was prepared.•The composite was quickly separated by magnet before and after adsorption process.•The composite adsorbed Congo red dye from aqueous solution effectively.•Pseudo-first order and Langmuir models best described the Congo red adsorption.•The composite adsorbent exhibits good reusability.