Abstract
A magnetically active composite as adsorbent was synthesized via a facile in situ one-pot impregnation of magnetic nano-iron oxide (Fe3O4) on the surface of activated carbon (AC) for the formation of AC-Fe3O4. Baker(')s yeast was physically loaded on the resultant adsorbent AC-Fe3O4 to form a novel yeast coated magnetic composite AC-Fe3O4-Yst as biosorbent. The two synthesized adsorbents were characterized by using a scanning electron microscope (SEM) and assessed using Langmuir, the Brunauer-Emmet-Teller (BET) and Dubinin-Radushkevich (D-R) isotherm models. The validity and applicability of these two sorbents in adsorptive removal of chromium species, Cr(VI) and Cr(III), from aqueous solutions under the effect of a magnetic field were studied and evaluated in the presence of various controlling parameters in order to identify the optimal pH, contact time, mass dose and chromium concentrations for such adsorption process. Also, single and multi-stage micro-column techniques were used to study the potential applications of AC-Fe3O4 as magnetically active adsorbents and AC-Fe3O4-Yst as magnetically active biosorbents, for the removal of chromium species from various real water samples.