REMOVAL OF CD 2+ IONS FROM BLOOD AND WATER SAMPLES BY FOLIC ACID MODIFIED SILICA NANOPARTICLES USING SOLIDPHASE EXTRACTION AND SORPTIVE-FLOTATION TECHNIQUES
In the present study, silica nanoparticles modified with folic acid(NS-FA)were synthesized and characterized using some instrumental techniques such as elemental analysis, scanning electron microscopy (SEM),Transmission electron microscopy (TEM) and FTIR. The modified silica nanoparticles were employed for removal of Cd 2+ from blood and water samples by two different separation techniques. For solid-phase extraction method, effect of some important parameters such as initial pH, temperature, contact time and adsorbate concentration were examined to evaluate the optimum adsorption conditions. The adsorption kinetics followed pseudo-second-order kinetic model showing hat the chemical adsorption is the rate-determining step. Also, the adsorption isotherm experiments revealed the best fit with Langmuir model and maximum adsorption capacity of 18.25 mg/g. For flotation method, a series of bench-scale experiments performed in the laboratory, targeting to assess the feasibility of using NS-FA as an efficient sorbent as well as oleic acid (HOL) as a surfactant. The effects of the process variables such as: initial solution pH, adsorbent, surfactant and cadmium concentrations and shaking time that influence the sorptive-flotation process were examined. Promising results were obtained under the optimum conditions, according to which nearly 100% of cadmium, at pH 6 and at room temperature (~25°C), was removed