o:1606 Sinteza, karakterizacija i primena hidrogelova na bazi N-izopropilakrilamida i anjonskih komonomera za uklanjanje hroma, mangana i olova iz vodenih rastvora Synthesis, characterization and application of hydrogels based on N-isopropylacrylamide and anionic comonomers for chromium, manganese and lead removal from aqueous solutions : doctoral dissertation sr In this doctoral dissertation, the hydrogels sensitive to temperature and pH changes based on N-isopropylacrylamide (NIPAM) and anionic comonomers (acrylic acid, AA, and methacrylic acid, MAA) were synthesized and investigated as adsorbent materials for removal of Cr(VI), Mn(II) and Pb(II) ions from aqueous solutions. The hydrogels were synthesized by radical polymerization process by varying the content of comonomer and crosslinker. The obtained poly(Nisopropylacrylamide- co-acrylic acid) (p(NIPAM/AA)) and poly(Nisopropylacrylamide- co-methacrylic acid) (p(NIPAM/MAA)) hydrogels were characterized using the following methods: Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), high pressure liquid chromatography (HPLC) and determining the swelling intensity in aqueous solutions of different temperatures and pH values. Kinetics of hydrogel swelling before and after the lyophilization process, as well as swelling reversibility through 3 alternate swell-shrink cycles under the influence of temperature were investigated. A full three-level experimental design was applied in order to describe the swelling of synthesized hydrogels as a function of temperature, pH value and crosslinker content by a mathematical model. Characterization of p(NIPAM/AA) and p(NIPAM/MAA) hydrogels with adsorbed metal ions was performed by FTIR and SEM method. Heavy metal ions in the structure of hydrogels were identified by energydispersive X-ray spectroscopy (EDX). The influence of pH, temperature, contact time and initial concentration of heavy metals on adsorption capacity of hydrogels was investigated. The kinetic and equilibrium data match best to the pseudo-second order model and Langmuir adsorption isotherm. Based on the thermodynamic results, it has been concluded that the adsorption of Cr(VI), Mn(II) and Pb(II) ions from aqueous solutions onto hydrogels was spontaneous and exothermic process. The adsorption capacity of p(NIPAM/AA) and p(NIPAM/MAA) hydrogels for investigated metal ions decreases in the following order: Pb(II)>Cr(VI)>Mn(II). Hydrogels based on NIPAM and AA or MAA are considered to be suitable adsorbents for removal of Cr(VI), Mn(II) and Pb(II) ions from aqueous solutions, due to high efficiency in the temperature range from 25 to 45 °C. Biografija autora: list 139;Bibliografija: listovi 140-146. Datum odbrane: 24.09.2019. Chemistry and chemical technology 534136470 91552101 7166 91552100 534136470 2020-01-28T17:12:04.053Z 45 no 46 mentor Aleksandar 1987- Zdravković 2019 63 mentor Ljubiša 1963- Nikolić 2019 63 član komisije Enis 1971- Džunuzović 2019 63 predsednik komisije Suzana 1967- Cakić 2019 63 član komisije Vesna 1965- Nikolić 2019 [12], 149 listova 14656876 http://phaidrabg.bg.ac.rs/o:1606 no yes 4 2020-01-28T17:12:04.320Z 70 hidrogel, bubrenje, difuzija, adsorpcija, teški metal, kinetika hydrogel, swelling, diffusion, adsorption, heavy metal, kinetics 544.773.432:66.095.26]:502/504(043.3) T 390 1738 18A08 18A0803 2019