An effective and recyclable adsorbent for the removal of mercury ions from aqueous system: nanomagnetic Fe3O4@SiO2@Si–(CH2)3–SH core-shell

In the present study, functionalized magnetic nanoparticles by 3-Mercaptopropyl-trimethoxysilane (MPTMS) for the removal of Hg2+ from aqueous solutions were synthesized. Scaning electron microscopy (SEM) and Fourier transform infrared spectroscopy analyses were used to determine the sorbent characterization. The effect of the operational parameters on the adsorption of Hg2+ by Fe3O4@SiO2@-Si-(CH2)3-SH such as initial pH, adsorbent dosage and the contact time were studied. In addition, the Langmuir and Freundlich isotherm models were applied to the equilibrium data at 25°C. The results revealed that the equilibrium data were fitted well with Freundlich than Langmuir isotherm model. The optimum adsorption capacity of Hg2+ onto Fe3O4 @ SiO2@-Si- (CH2) 3-SH was determined as 20.04 (mg/g) at initial solution PH of 6.0, adsorbent dosage of 30 mg, 15 min contact time. The Hg2+ adsorption kinetic was well described by the pseudo-second order kinetic model. Desorption and regeneration of nanosorbent was investigated. The results showed that the nanosorbent can be regenerated for six times with acceptable sorption capacity.