Novel ternary nanohybrids of tetraethylenepentamine and graphene oxide decorated with MnFe2O4 magnetic nanoparticles for the adsorption of Pb(II)

Novel ternary nanohybrids, consisting of tetraethylenepentamine (TEPA), graphene oxide (GO) and manganese ferrite magnetic nanoparticles (TEPA-GO/MnFe2O4), were prepared by a facile hydrothermal method and utilized to remove Pb(II) from aqueous solution effectively. The adsorbents were characterized by SEM, TEM, XRD, FTIR, zeta potential analysis, magnetization hysteresis loop, BET and XPS. These nanoparticles exhibited superparamagnetic behavior as well as high removal efficiency for Pb(II). Moreover, numerous amino groups of the functionalized pendant TEPA on GO coupled with the porous structure of TEPA-GO/MnFe2O4 contribute to high Pb(II) adsorption capacity. The maximum Pb(II) adsorption capacity of TEPA-GO/MnFe2O4 was determined to be 263.2 mg/g at the optimized solution pH of 5.5, much higher than that of GO/MnFe2O4 (133.3 mg/g) and GO (196.1 mg/g). The kinetics and isotherm data fitted well with the pseudo-second-order kinetics and the Langmuir isotherm model, respectively. Thermodynamic studies revealed that the Pb(II) adsorption of TEPA-GO/MnFe2O4 was a endothermic and spontaneous process. The experimental results corroborated that TEPA-GO/MnFe2O4 can be efficaciously reused after washed with HCl, indicative of its potential applications in environmental cleanup.