Nanocomposites and nanomaterials 

Sorption properties of silica gel with adsorbed poly [8-oxyquinoline methacrylate] on Cu (II) Cd (II), Pb (II) and Fe (III) ions

Savchenko1, E. Yanovska1,  D. Sternik2, O. Kychkyruk3

1 National Taras Shevchenko University of Kyiv,
60, Volodymyrska str., 01601 Kyiv, Ukraine
E-mail: iras@univ.kiev.ua
2 Maria Curie-Skłodowska University, pl. Maria Curie-Skłodowskiej 3, 20‑031 Lublin, Poland
3 Ivan Franko Zhytomyr State University, 40 Velyka Berdychivska St., 10008 Zhytomyr, Ukraine

Recently, the efforts of researchers are aimed at finding methods for targeted one-stage synthesis of sorbents with a monofunctional coating of a solid surface with substances that are capable of complexation. In particular, to increase the efficiency of sorbents against transition metal ions on the developed surface of porous inorganic carriers are increasingly fixed polyfunctional polymers that have both complexing and ion exchange properties (polyonenes, polyhexamethylene guanidine and its derivatives, polyaniline, polyacrylic). However, in such polymers ion exchange properties significantly outweigh the complexing ones. Therefore, the search for methods for the synthesis of organo-mineral composite materials, which include polymers exclusively with complexing properties, remains relevant.
By adsorption on the surface of silica gel poly [8-oxyquinoline methacrylate], synthesized by initiated radical polymerization, a new composite material was obtained.
Immobilization of poly [8-oxyquinoline methacrylate] on the silica gel surface was confirmed using IR spectroscopy and thermogravimetric analysis combined with mass spectroscopy. Using thermogravimetric analysis, it was found that the mass fraction of polymer in the synthesized composite is 43.5%.
From the analysis of photographs of the surface of the synthesized composites obtained by scanning electron microscopy, it follows that the polymer is on the surface of silica gel in the form of agglomerates of various shapes, which cover most of the surface of the silica gel particles.
As a result of studying the sorption capacity of the synthesized composite with respect to Cu (II), Cd (II), Pb (II) and Fe (III) ions, a rather high degree of sorption of milligram amounts of the studied ions was recorded: Cd2+  at the level of 93-98%, Fe3+ - 91- 96%, Cu2+- 90-96%,  Pb2+- 71-89%. The sorption capacity in comparison with the capacity for the original silica gel increases relative to Cu (II) ions 20 times, relative to Pb (II) and Fe (III) ions - 16 times, Cd (II) - 6.5 times. The obtained data correlate well with the values of the stability constants of the complexes of these metals with 8-oxyquinoline.
The synthesized composite has a higher sorption capacity relative to Pb (II), Cu (II) and Fe (III) ions compared to the capacity for silica gel with in situ immobilized poly [8-oxyquinoline methacrylate]. This is due to the greater amount of adsorbed polymer compared to the in situ immobilized polymer, and hence the presence of more active centers for complexation on the modified surface of the silica gel.