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- 저자 : M. R. El-Aassar (검색결과 2 건)
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M. R. El-Aassar,Mahmoud H. M. A. Shibraen,Yasser R Abdel-Fattah,Ahmed A. Elzain 한국섬유공학회 2019 Fibers and polymers Vol.20 No.11
Enzyme immobilization onto nanomaterials is a strategy to overcome the difficulties of the free enzymesapplications where the immobilization process affords excellent reusability and operational stability against temperature andpH, and high surface area for the catalytic reaction. In this work, poly(Acrylonitrile-co-Styrene/Pyrrole), (poly(AN-co-ST/Py)), copolymer nanofibers were successfully fabricated using the electrospinning technique. Laccase enzyme from Trametesversicolor was immobilized onto functionalized poly(AN-co-ST/Py) nanofibers by covalent attachment usingpolyethylenediamine (PEI) via physical adsorption and multipoint covalent attachment to the functional groups onto thepolymeric surface. Since the relative activity of the immobilized Laccase depends on the amount of the coupled PEI onto thepolymeric nanofibers, a colorimetric assay via copper ions complex formation was applied for the estimation of the processyield. Accordingly, the various factors affecting the PEI coupling process such as concentration, time, pH and temperaturewere investigated; Besides their influence on the morphology of the resultant nanofibers. Furthermore, thermal and pHstability, storage stability, and reusability were evaluated and compared. The optimum reaction temperature and pH for theimmobilized enzyme were 70 oC and 6.0, respectively. The scanning electron microscopy (SEM) images showed that themodified nanofibers with PEI have kept its nanofibers structure and uniform morphology with an average diameter ofapproximately 559.2 nm. Within 35 days, the immobilization process reduces the activity loss from 59 % to 29 %, whilethermal incubation at 50 oC for 2 hrs causes activity loss for the free and immobilized enzymes by 65 % and 30 %respectively. Therefore, the prepared copolymer nanofibers proposed in this work showed promising potential forapplications to enzyme immobilization.
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Ahmed S. M. Ali,M. R. El-Aassar,F. S. Hashem,N. A. Moussa 한국섬유공학회 2019 Fibers and polymers Vol.20 No.10
This paper concerns with the enhancement of a safe and clean procedure for remediation of water pollution. Cellulose acetate (CA) nanofibers were prepared via electrospinning technique prior to surface modification with polyaniline/β-cyclodextrin (PANI/β-CD) nanocomposite. Morphology and structure of the modified CA nanofibers were characterizedby different analysis like X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electronmicroscopy (SEM) and Thermogravimetric analyses (TGA). We studied the influence of modification of CA with PANI/β-CD nanocomposite for removal of cationic dyes from colored aqueous solution in dynamic batch mode. Methylene blue(MB) dye was selected as a cationic dye model for the study. The effects of various parameters like pH, nanosorbent dose,dye concentration and reaction time on the adsorption capacity were studied. Some mathematical isotherm and kineticmodels have been utilized to investigate the adsorption mechanism of MB into the CA-PANI/β-CD nanofibers. Thereusability of the CA-PANI/β-CD nanofibers was also verified in sequent cycles and rapid process was detected. Differentreal water samples like tap water, industrial wastewater, municipal wastewater and sea water were applied to test the MBremoval efficiency.
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