Hybrid composite sorbents based on SiO 2 /PLGA for Fe(III) ions removal

SiO2/PLGA(poly(d,l-lactic acid-co-glycolic acid)-based composites were synthesized using the single-stage sol–gel technique in acetone. The composition of the obtained materials was studied by means of the CNHS analysis, pH-potentiometric acid–base titration, zeta potential measuring, IR spectroscopy, TGA, low-temperature nitrogen adsorption method, SEM, EDX analysis, and photon cross-polarization spectroscopy. On the basis of physical and chemical method data, it was found that the synthesized hybrids are spherical samples of up to 250 nm with an organic component content of up to 18.5% (mass.), and an acid groups content of up to 1.47 mmol/g. The composites were applied as adsorbents of Fe (III) ions from aqueous solutions. It was found that the optimum pH value for adsorption was 4.0, and the adsorption equilibrium time was 240 min. The adsorption kinetics was also considered, it was revealed that kinetics obeyed the Lagergren pseudo-second-order model and chemisorption takes place during the adsorption. The results also showed that hybrid composites selectively adsorb Fe (III) ions from aqueous solutions containing the equal amount of Cu (II), Mn (II), Ni (II), and Fe (III) ions (~ 20 mg/l).