Synthesis of magnetic Fe-carbon nanohybrid for adsorption and Fenton oxidation of tetracycline

This work focuses on developing an efficient water decontaminant system based on magnetic carbon nanohybrid. To achieve this goal, MnFe2O4 nanoparticles were synthesized by simple coprecipitation method then nitrogen- doped polyphenol resin was prepared by cross-linking of phenylenediamine and resorcinol over MnFe2O4 nanoparticles. The prepared magnetic composite was heat treated in an argon atmosphere at 800 degrees C for 2 h. Characterization of the heat treated nanohybrid with XRD revealed that the iron oxide phase changed to zero-valent iron nanoparticles. Moreover, transmission electron microscopy image, and Brunauer, Emmett and Teller analysis confirmed that the nanohybrid possesses a mesoporous structure with the surface area of 153.1 m(2)/g. Prepared nanohybrid was employed for tetracycline removal from aqueous solution with adsorption and Fenton oxidation processes. Effective parameters on the adsorption process such as pH, time, adsorbent dosage, ionic strength and H2O2 amount were optimized with response surface methodology. For the adsorption process, kinetic models were also studied within 7 min of equilibrium time. Results confirmed that tetracycline adsorption followed the pseudo-first-order kinetic model. Isotherm study showed that Freundlich model can better describe the adsorption process moreover Dubinin-Radushkevich model showed the adsorption is a physical process. The maximum adsorption capacity of 103 mg/g was obtained. Fenton oxidation can effectively increase the removal percentage since at an initial concentration of 100 mg/L, the removal efficiencies were 28.5% and 91.8% by the adsorption experiment and Fenton process, respectively.