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M Vinoba M Bhagiyalakshmi SK Jeong SC Nam Y Yoon 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(38):12028-12034
Bovine carbonic anhydrase (BCA) was covalently immobilized onto OAPS (octa(aminophenyl)silsesquioxane)-functionalized Fe(3) O(4) /SiO(2) nanoparticles by using glutaraldehyde as a spacer. The Fe(3) O(4) nanoparticles were coated with SiO(2) , onto which was grafted OAPS, and the product was characterized using SEM, TEM, XRD, IR, X-ray photoelectron spectroscopy (XPS), and magnetometer analysis. The enzymatic activities of the free and Fe(3) O(4) /SiO(2) /OAPS-conjugated BCA (Fe?CA) were investigated by hydrolyzing p-nitrophenylacetate (p-NPA), and hydration and sequestration of CO(2) to CaCO(3) . The CO(2) conversion efficiency and reusability of the Fe?CA were studied before and after washing the recovered Fe?CA by applying a magnetic field and quantifying the unreacted Ca(2+) ions by using ion chromatography. After 30?cycles, the Fe?CA displayed strong activity, and the CO(2) capture efficiency was 26-fold higher than that of the free enzyme. Storage stability studies suggested that Fe?CA retained nearly 82?% of its activity after 30?days. Nucleation of the precipitated CaCO(3) was monitored by using polarized light microscopy, which revealed the formation of two phases, calcite and valerite, at pH?10 upon addition of serine. The magnetic nanobiocatalyst was shown to be an excellent reusable catalyst for the sequestration of CO(2.). 相似文献
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Mesoporous SBA-15 was synthesized using rice husk ash (RHA) as the silica source and their defective Si-OH groups were grafted with tris(2-aminoethyl) amine (TREN) dendrimers generation through step-wise growth technique. The X-ray diffraction (XRD) and nitrogen adsorption/desorption results of parent SBA-15 obtained from RHA, suggests its resemblance with SBA-15 synthesized using conventional silica sources. Furthermore, the nitrogen adsorption/desorption results of SBA-15/TREN dendrimer generations (G1-G3) illustrates the growth of dendrimer inside the mesopores of SBA-15 and their CO2 adsorption capacity was determined at 25 °C. The maximum CO2 adsorption capacity of 5-6 and 7-8 wt% over second and third dendrimer generation was observed which is discernibly higher than the reported melamine and PAMAM dendrimers. The experimental CO2 adsorption capacity was found to be less than theoretically calculated CO2 adsorption capacity due to inter and intra molecular amidation as result of steric hindrance during the dendrimer growth. These SBA-15/TREN dendrimer generations also exhibit thermal stability up to 350 °C and CO2 adsorption capacity remains unaltered upon seven consecutive runs. 相似文献
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Dr. Mari Vinoba Dr. Margandan Bhagiyalakshmi Dr. Soon Kwan Jeong Dr. Sung Chan Nam Dr. Yeoil Yoon 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(38):12028-12034
Bovine carbonic anhydrase (BCA) was covalently immobilized onto OAPS (octa(aminophenyl)silsesquioxane)‐functionalized Fe3O4/SiO2 nanoparticles by using glutaraldehyde as a spacer. The Fe3O4 nanoparticles were coated with SiO2, onto which was grafted OAPS, and the product was characterized using SEM, TEM, XRD, IR, X‐ray photoelectron spectroscopy (XPS), and magnetometer analysis. The enzymatic activities of the free and Fe3O4/SiO2/OAPS‐conjugated BCA (Fe? CA) were investigated by hydrolyzing p‐nitrophenylacetate (p‐NPA), and hydration and sequestration of CO2 to CaCO3. The CO2 conversion efficiency and reusability of the Fe? CA were studied before and after washing the recovered Fe? CA by applying a magnetic field and quantifying the unreacted Ca2+ ions by using ion chromatography. After 30 cycles, the Fe? CA displayed strong activity, and the CO2 capture efficiency was 26‐fold higher than that of the free enzyme. Storage stability studies suggested that Fe? CA retained nearly 82 % of its activity after 30 days. Nucleation of the precipitated CaCO3 was monitored by using polarized light microscopy, which revealed the formation of two phases, calcite and valerite, at pH 10 upon addition of serine. The magnetic nanobiocatalyst was shown to be an excellent reusable catalyst for the sequestration of CO2. 相似文献
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