D. Peshev

Removal of cadmium and copper ions by Trichosporon cutaneum R57 cells immobilized onto polyvinyl alcohol/tetraethoxysilane hybrid matrices

AbstractPolyvinyl alcohol (PVA) and tetraethoxysilane (TEOS) hybrid materials were prepared by sol-gel methods and tested as matrices for immobilization of Trichosporon cutaneum R57, capable of removing cadmium and copper ions from aqueous solutions. A kinetic model was applied and the effects of matrix TEOS content on the copper and cadmium uptake equilibria and rate constants were investigated.

PVA -based Hybrid Materials for Immobilization of Trichosporon cutaneum R57 Efficient in Removal of Chromium Ions

New hybrid materials based on polyvinyl alcohol (PVA) and γ-aminopropyltriethoxyxilane (APTEOS), 3-mercaptopropyltriethoxysilane (MPTEOS) and tetraethoxysilane (TEOS) were prepared. To determine the thermal stability of the hybrid materials, thermogravimetric analysis (TGA) was performed. The new materials were tested for biofilm formation and biosorption studies. They were tested as matrices for immobilization of Trichosporon cutaneum R57 capable to remove Cr(VI) from aqueous solutions. The use of APTEOS and MPTEOS as precursors, incorporated new NH– and SH– bonds, which ensured additional binding places for cells immobilization. The presence of SH– and NH– groups in the hybrid matrices resulted in apparently higher Cr(VI) sorption capacity of the immobilized Tr. cutaneum R57 cells due to the incorporation of additional adsorption sites in the matrix through the PVA functionalities. The synthesized PVA/APTEOS materials proved efficient for use in biosorption applications.