Boron removal and reclamation by magnetic magnetite (Fe3O4) nanoparticle: An adsorption and isotopic separation study

摘要

Magnetic magnetite nanoparticle (MMN) was studied as an adsorbent for effective boron removal and isotopic separation in aqueous solution for the first time. The adsorption equilibrium was reached rapidly in 1.5 h, and a high capacity of 4.57 mmol/g was achieved at pH = 7 at 45 degrees C. Quasi second-order kinetic model and Henry isotherm suitably described boron adsorption on magnetite nanoparticles. Furthermore, magnetite nanoparticles showed better affinity for B-10, and a high boron isotopic separation factor (S) of 1.332 was observed at pH = 6 and 15 degrees C. The adsorption was a spontaneous chemisorption process where the entropy effect is the main driving force instead of enthalpy change. The FTIR and XPS spectra of boron-encapsulated MMN indicated the formation of new Fe-O-B bonds. High boron adsorption capacity, excellent boron isotope separation factor, low cost and easy regeneration empower MMN as an adsorbent of great practical value for boron removal and isotope reclamation.