Separation/Preconcentration of Al(III) from Water Samples via Sorptive-Flotation Technique Using Silica Nanoparticles Modified with Folic Acid

In the present work, silica nanoparticles functionalized with folic acid (Nano-SiO2-FA) were synthesized and characterized thru elemental analysis, infrared spectroscopy (FT-IR), Brunauer-Emmett-Teller (BET) surface area determination, and scanning electron microscope (SEM). Nano-SiO2-FA was examined as a sustainable and promising sorbent for preconcentration of Al(III) from natural water samples by sorptive-flotation (SF) separation technique before its determination by flame atomic absorption spectrometry (FAAS). A several trials were made in lab, to determine the feasibility of using Nano-SiO2-FA as a sorbent and oleic acid as a surfactant. The influence of: Solution pH, temperature, shaking time, surfactant, sorbent and Al(III) concentration and the presence of foreign ions that affect the sorptive-flotation process were investigated. Good results attained under optimum circumstances, at pH 3.5 and ∼25°C, according to which nearly 100% of aluminum was separated. The procedure was successfully applied to recover aluminum spiked to some natural water samples. Moreover, a sorption and flotation mechanism is suggested.