Karolina Gdula

Functionalized SBA-15 organosilicas as sorbents of mercury(II), cadmium(II) and copper(II)

Amino- and thiol-functionalized SBA-15 organosilicas have been synthesized by co-condensation of tetraethoxysilane (TEOS) with appropriate trifunctional silanes i. e. aminopropyltriethoxysilane (ATES) and mercaptopropyltriethoxysilane (MTES). The materials were characterized by nitrogen sorption measurements, XRD diffractometry, FTIR/PAS spectroscopy and SEM, TEM and AFM microscopy. The obtained materials exhibit high porosity, good ordering, and high content of functional groups (0.5–1.5 mmol/g). These materials have been tested as sorbents for three bivalent metal ions: Hg(II), Cd(II) and Cu(II) testifying to their usefulness in such sorption applications. The adsorption kinetics was were favour-able-all the metal ions were adsorbed just after several minute and the amounts of adsorbed metals were high and depended on the type and content of surface functionalities.

Adsorption of L-Histidine onto Functionalized Mesoporous SBA-15 Organosilicas

Adsorption of L-histidine (LH) over mesoporous SBA-15 silicas functionalized by amine-, thiol- and cyano-functional groups has been studied. These organosilicas have been synthesized by co-condensation of proper monomers in the presence of a template (Pluronic P-123), and characterized by elemental analysis, nitrogen adsorption, X-ray diffraction and transmission electron microscopy. The highest LH static adsorption capacity was observed for the cyano-functionalized sample [approximately 70 mg g−1 (450 mol g−1)]; by contrast, pristine SBA-15 had a lowest adsorption capacity of approximately 25 mg g−1 (170 mol g−1).

Characteristics of surface and electrochemical properties of composites with fumed metal oxides and hydroxyapatite

Hydroxyapatite composite is a very important biomaterial, which can be applied in various life areas. Hydroxyapatite and its composites with fumed oxides ST20, AST1, Al2O3, A90, and A300 were prepared and studied using X-ray diffraction, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy adsorption, potentiometric titration, quasi-elastic light scattering and zeta potential measurements. The values of pHpzc (the point of zero charge) and pHIEP (the isoelectric point) characteristic of the electrical double layer depend on the type of the fumed oxide matrix. Comparative studies of hydroxyapatite, fumed oxides and composites by adsorption and desorption of nitrogen, scanning electron microscopy and FTIR showed that in most cases composites have properties intermediate between hydroxyapatite and the oxides taken for the synthesis.

Amine-functionalized silica particles with magnetic core as magnetically removable adsorbents of Ag(I) ions

Adsorption of silver ions over amine-functionalized silica particles with magnetic core has been studied. This adsorbent has been synthesized via sol–gel method, in the presence of Fe3O4 particles as magnetic cores. As a comparison, magnetic silica adsorbent with non-functionalized surface was also synthesized. As-obtained materials have been characterized by elemental analysis, acid–base titration, nitrogen sorption measurements, X-ray photoelectron spectroscopy and scanning electron microscopy. What is more, parameters of electrical double layer at the silica adsorbent/electrolyte solution interface were also examined. Kinetic of adsorption and isotherms of silver ions were determined. The obtained adsorption of Ag(I) ions for the studied materials was in the range of about 0.2–0.3 mmol/g.

Protection of Thiol Groups on the Surface of Magnetic Adsorbents and Their Application for Wastewater Treatment

The magnetite nanoparticles were functionalized with silica shells bearing mercaptopropyl (monofunctional) and mercaptopropyl-and-alkyl groups (bifunctional) by single-step sol-gel technique. The influence of synthetic conditions leading to increased amounts of active functional groups on the surface and improved capacity in the uptake of Ag(I), Cd(II), Hg(II), and Pb(II) cations was revealed. The physicochemical properties of obtained magnetic nanocomposites were investigated by FTIR, Raman, XRD, TEM, SEM, low-temperature nitrogen ad-/desorption measurements, TGA, and chemical microanalysis highlighting the efficiency of functionalization and mechanisms of the preparation procedures. The removal of the main group of heavy metal cations was studied in dependence from the pH, contact time and equilibrium concentration to analyze the complexes composition for the large scale production of improved adsorbents. It was demonstrated that introduction of the alkyl groups into the surface layer prevents the formation of the disulfide bonds between adjacent thiol groups. The obtained adsorbents were employed to treat real wastewater from Ruskov, Slovakia with concentration of Fe 319 ng/cm3, Cu 23.7 ng/cm3, Zn 36 ng/cm3, Mn 503 ng/cm3, Al 21 ng/cm3, As 34 ng/cm3, Pb 5.8 ng/cm3, Ni 35 ng/cm3, Co 4.2 ng/cm3, Cr 9.4 ng/cm3, Sb 6 ng/cm3, Cd 5 ng/cm3. These materials proved to be highly effective in the removal of 50% of all metal ions, espeсially Zn, Cd, and Pb ions from it and turned recyclable, opening for their sustainable use in water purification.

Iron Oxides and Their Silica Nanocomposites as Biocompatible Systems for Biomedical Applications

This chapter is dedicated to iron oxides as well as their composites, in nanometer scale. Such systems are representatives of magnetic nanoparticles. In this chapter, most popular synthesis routes, properties, and applications, mainly in biomedical fields, will be presented. Magnetic nanoparticles (MNPs) have made a special contribution in the development of many fields of science and industry, e.g., electronic, medicine, biotechnology, and so on. Iron oxides, especially γ-Fe2O3 (maghemite) and Fe3O4 (magnetite), are one of the most primary known examples of MNPs. What is more, they are of still interest to many technologists and are particularly interesting subjects of many researches. A big challenge is to develop optimal conditions for synthesis of the magnetic composites to achieve systems with specific properties, as well as their further study allowing the best usage of the obtained nanocomposites.

Thiol-Functionalized Mesoporous Carbons as Adsorbents of Heavy-Metal Ions

Ordered mesoporous carbon has been obtained by hard templating using SBA-15 and subsequently, oxidized (by treatment with ammonium persulphate) and thiol-functionalized (by treatment with thiol-contained polyhedral oligomeric silsesquioxane). Pristine and thiol-functionalized carbons were characterized by nitrogen adsorption, X-ray diffractometry, X-ray photoelectron spectroscopy, scanning electron microscopy and transmission electron microscopy and tested for their ability to adsorb bivalent heavy-metal ions (Cd, Cu, Pb, Zn) from the aqueous solutions. The observed static adsorption capacities are very high up to 0.76 mmol/g. Adsorption kinetics is also very fast: approximately 90% of the equilibrium amount is adsorbed after several minutes.

Nanoporous Silica-Based Materials for Sorption of Pharmaceuticals and Biomolecules

Abstract Our concern in this paper is to review four kinds of mesoporous silica materials which can be used as potential sorbents for pharmaceuticals. It is known that a continuous development of science, medicine and food industry has an effect on contamination of the natural environment. Moreover, many impurities, such as drugs, vitamins or proteins etc., which get into environment from urban and hospital wastes, can also influence on human organisms. Thus, there is a need to control an amount of those compounds, especially in the natural waters and wastewaters [1-4]. In this work, we present four types of silica materials which can be helpful in water purification by using adsorption process.

An effective scaling frequency factor method (ESFF): review and local factors transferability problem

Abstract Scaling procedures are known to reproduce very accurate vibrational spectra provided that multiparameter scaling in conjunction with high-quality force fields is carried out. In contrast to purely theoretical approaches (variational and perturbational), they are applicable to large systems. In this work, a brief review of the scaling procedures is given. The emphasis is put on the recently proposed effective scaling frequency factor (ESFF) method [Chem. Phys. Lett., 446, 191, (2007), J. Mol. Spectr., 264, 66, (2010)] - the multiparameter frequency scaling method providing better scaled frequencies than the well-established scaled quantum mechanical (SQM) force field approach. In addition, the results of our calculations on the benzene-based related systems, i.e., benzene and most of its methyl derivatives, are presented. The calculations concern the middle- and low-frequency range of the vibrational spectra, where strong mixing of the local vibrations often takes place. The factors transferability problem is discussed.