One-pot growth and characterization of α-Fe2O3/β-FeOOH micro-nanosystem for industrial dye removal

Abstract

A micro-nanosystem of α-Fe2O3/β-FeOOH was developed for the first time using a one-pot hydrothermal method. The synthesis mechanism of the simultaneous development of micro-sized α-Fe2O3 and nano-sized β-FeOOH is discussed. The structural properties studied via X-ray diffraction (XRD) revealed the presence of both phases, whereas the FESEM study confirms that α-Fe2O3 and β-FeOOH are of microdisc and nanohusk type, respectively. Considering the two different shapes and sizes of particles in a micro-nanosystem, α-Fe2O3/β-FeOOH was used to remove rhodamine B dye. The hydrogen bonding between the adsorbent and the RhB dye influences the binding properties. The mixed-shaped iron-based particles have provided maximum adsorbing sites which have strengthened the bonding between the adsorbent and adsorbate. The FTIR study was used to confirm the binding of RhB dye with the micro-nanosystems. Adsorption capacity and removal efficiency for α-Fe2O3/β-FeOOH micro-nanosystem adsorbent were found to be 727 mg g−1 and 91 % respectively. The binding mechanism along with the adsorption isotherm and adsorption kinetic study, has been discussed. The adsorption isotherm study confirms that the adsorption process followed the Freundlich isotherm model. The adsorption kinetic study suggested the well-fitting of pseudo-first-order kinetics and the Elovich model with the adsorption process. The reusability study of the micro-nanosystem confirms that the micro-nano system can retain the highest removal efficiency up to 4th cycle. Further, the fabricated micro-nanosystem was applied for the removal of RhB dye from the real water samples, collected from different sources.