Fe-TiOx nanoparticles on pineapple peel: Synthesis, characterization and As(V) sorption

Effective Fe-TiOx magnetic nanoparticles were synthesized on pineapple-peel (CPa-Fe/TiOx) to evaluate their As(V) uptake capacity. The nanocomposite was characterized by means of BET surface analysis, SEM, TEM, XRD, FTIR and XPS. The results indicated the obtention of spherical nanoparticles with 5.7 nm of diameter distributed on the surface of pineapple peel with a Ti:Fe molar ratio of 2:1, while DRX indicate that the material is amorphous. IR spectra of the obtained CPa-Fe/TiOx present a number of bands at 3316, 2924, 2852, 1729, 1632, 1371, 1241, 1035, 590 and 545, indicating the existence of hydroxyl and carboxyl groups on the composite material. The nanocomposite was evaluated as an adsorbent of As(V) and experimental parameters as time, pH, concentration and temperature were evaluated. CPa-Fe/TiOx were effective at pH = 5.5, sorption isotherms showed that sorption capacities of the Fe-TiOx, were dependent on the site density, surface area and temperature change. The equilibrium data was modelled with the help of Langmuir and Freundlich equations, based on the values of correlation coefficients (R2) the Langmuir isotherm equation was excellently fitted to the experimental data of the arsenic adsorption with a maximum adsorption uptake of 40 mg/g under the studied conditions. The thermodynamic results showed that the sorption of As(V) onto CPa-Fe/TiOx was feasible, spontaneous and exothermic, through mechanism ligand effect-surface, with the interaction between oxy-hydroxides of Fe and Ti with oxy-anions of arsenic present in solution.