, Atefeh Jafari, Komail Boustani, Mojtaba Salouti,
Volume 12, Issue 4 (11-2013)
Abstract
In this study, Fe3O4/SiO2 core-shell magnetic nanoparticles (NPs) by two-step process were synthesized. First, Fe3O4 NPs by co-precipitation method of iron ions (Fe3+ and Fe2+) in an alkaline medium without using surfactant were synthesized and then silica shell with a non-thermal method without the use of linkers were installed on Fe3O4 NPs. facility of this method is noticeable. Results of X-ray powder diffraction patterns show that the inverse spinel structure of Fe3O4 and amorphous silicon was made. Fourier transform infrared spectroscopy confirmed the formation of these structures. There is no additional peak in XRD pattern which indicates that the prepared particles have pure Fe3O4 phase. TEM images show that core-shell structure is formed and mean size of NPs is 20 nm. VSM analysis showed that saturation magnetization of Fe3O4 nanoparticles after coating with silicon decreased.
Salman Ahmady-Asbchin, Naser Jafari,
Volume 15, Issue 1 (4-2015)
Abstract
Abstract
Methods of physical and chemical adsorption of heavy metals, has some disadvantages such as high cost and are ineffective at low concentrations. Methods for biological uptake of heavy metals in recent decades were considered. Among the biological adsorbent include: bacteria, fungi and alga, algae have the highest efficiency of metal uptake. This study determined that the main role in the uptake of metals, nickel (II) and cadmium (II) Alginic acid is responsible. Focus serratus brown alga, as adsorbent in this study used a cost-effective biological and biological uptake of cadmium and nickel ions simultaneously in a batch reactor has been studied. Surface structure of algae has been studied. Adsorption kinetics have been studied, the equilibrium time is about 300 minutes, the Langmuir adsorption isotherm using the equation can be interpreted as the maximum adsorption of about 0/85and 0/95mmol/g are, respectively, for cadmium(II) and nickel(II).
