Abstract
Reduced-graphene-oxide based superparamagnetic nanocomposite (GC) was fabricated and applied for the remediation of Ni(II) from an aqueous medium. The as-prepared GC was extensively characterized by Raman, TEM, AFM, SEM-EDX, SQUID, and BET analyses. Quantitative immobilization of Ni(II) in an aqueous solution by the fluorescent sensor platform of GC was explored at varying pH, doses, contact times, and temperatures. The pseudo-second-order kinetics equation governed the overall sorption process at optimized pH of 5 (±0.2). The superior monolayer sorption capacity was 228mgg-1 at 300K. Negative δG0 indicated the spontaneous sorption nature, whereas the positive δH0 resulted from an increase in entropy (positive δS0) at the solid-liquid interface during the endothermic reaction. The lower enthalpy agreed with the relatively high regeneration (approximately 91%) of the GC by 0.1M HCl, because of the formation of stable tetrahedral complex. The physisorption was well corroborated by calculated sorption energy (EDR ~7kJmol-1) and the nature of the Stern-Volmer plot of the fluorescence-quenching data with reaction time. The GC played a pivotal role as a static fluorescent sensor platform (fluorophore) for Ni(II) adsorption. Magnetic property also indicated that GC could be easily separated from fluids by exploiting its superparamagnetic property.
Original language | English |
---|---|
Pages (from-to) | 69-79 |
Number of pages | 11 |
Journal | Journal of Colloid and Interface Science |
Volume | 454 |
DOIs | |
Publication status | Published - 5 Sept 2015 |
Keywords
- Adsorption
- Fluorescence sensing technology
- Magnetic separation
- Water purification
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Biomaterials
- Surfaces, Coatings and Films
- Colloid and Surface Chemistry