Browsing by Author "Mahmoud, Ghada A"

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    Alkali-cellulose/ Polyvinyl alcohol biofilms fabricated with essential clove oil as a novel scented antimicrobial packaging material
    (Elsevier Ltd., 2022-12) Sayed, Asmaa; Safwat, Gehan; Abdel-raouf, Manar; Mahmoud, Ghada A
    The increased environmental awareness issues encouraged the manufacture of food -wares and packaging items from cellulosic materials to cope with the rapid growth of fast- food industry. In this work, scented biofilms with potent antimicrobial activity were prepared in a multi-step process assisted with the AFM. The biofilms comprised of polyvinyl alcohol (PVA) physically crosslinked with different weight ratios of alkaline cellulose (Na-Cell) [PVA/Na-Cell]. Then, the effect of gamma irradiation on the surface features of the optimized sample (PVA/Na-Cell4) was verified at 5-25 KGy. The optimum film (PVA/Na- Cell4.20kGy) was fabricated with different weight ratios of essential clove oil (ECO). The biofilms were characterized by the AFM, FT-IR, XRD, TGA, and the DMA. The contact angle measurements of the optimized films reveal wettability resistance as following: PVA/Na-Cell4.0kGy (102.48o ) < PVA/Na-Cell4.20kGy (133.66o )< PVA/Na-Cell4.ECO20kGy (140.62o ). The antimicrobial investigation displayed remarkable effect against different pathogens. Therefore, the claimed biofilms are excellent candidates for packaging application.
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    Characterization and optimization of magnetic Gum-PVP/SiO2 nanocomposite hydrogel for removal of contaminated dyes
    (Elsevier, 19/01/2022) Sayed, Asmaa; Mahmoud, Ghada A; Said, Heba.; Diab, Ayman A
    Gum-polyvinylpyrrolidone/silica (Gum-PVP/SiO2) nanocomposite hydrogel was prepared using gamma radiation-induced copolymerization and crosslinking. The magnetic nanocomposite hydrogel was carried out by in situ method. The structure of the magnetic and non-magnetic nanocomposite hydrogel was investigated and analyzed by FTIR, XRD, and TEM analysis. The swelling percentage decreases with increasing radiation dose due to the cross-linking is increasing by the irradiation dose. The factors that affect the adsorption behavior of the nanocomposite hydrogel toward basic and acidic dyes were studied. The magnetic nanocomposite hydrogel response a bit higher adsorption properties than the non-magnetic one. On the other hand, the nanocomposites showed better adsorption behavior towards Fuchsine basic dye (FC) than the methyl orange acidic dye (MO). The prepared nanocomposite has high adsorption efficiency that is recommended in treatment of dye effluents
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    Multiwalled carbon nanotubes@pectin/κ-carrageenan-based nanocomposite biohydrogel prepared by gamma irradiation for efficient methylene blue dye sequestration
    (John Wiley & Sons Inc, 2024-03) Aboelkhir, Doaa M; Sayed, Asmaa; Eldondaity, Leila S; Joseph, Veronica; Amin, Ayman; Mahmoud, Ghada A
    This study addresses the critical issue of removing toxic dyes from industrial wastewater to protect the environment and human health. To address this challenge, a bio-based composite hydrogel was synthesized using gamma irradiation, 20 kGy, incorporating multiwalled carbon nanotubes@pectin/κ-carrageenan/polyacrylic acid (MWCNTs PC/KC/PAAc) for removing methylene blue (MB) dye from aqueous solutions. The prepared composites underwent characterization through Fourier-transform infrared spectroscopy, x-ray diffraction, and thermogravimetric analyses. Brunauer–Emmett–Teller analysis demonstrated a significant increase in surface area upon the addition of MWCNTs. Specifically, the surface area increased from 342.5 m2 g−1 for PC/KC/PAAc to 689.5 m2 g−1 when 0.175 wt% of MWCNTs were added. Also, scanning electron microscopy and atomic force microscopy were utilized to examine the surface topography of PC/KC/PAAc and MWCNTs@PC/KC/PAAc. The results reveal that at 0.175 wt% of MWCNTs, there was a more uniform surface topography with well-distributed MWCNTs within the matrix. In the adsorption study of MB dye, it was found that the highest MB removal efficiency was achieved at pH 11, with values of 68.21% and 96% for PC/KC/PAAc and MWCNTs@PC/KC/PAAc, respectively. Furthermore, upon studying the effect of MWCNTs (%), the results showed that the removal (%) of PC/KC/PAAc was 68.21 ± 1.02%, and this percentage increased rapidly with the addition of MWCNTs, reaching a maximum of 96 ± 0.85% when 0.175 (wt%) of MWCNTs was added. Isotherm and kinetic modeling demonstrated that MB adsorption follows the Freundlich isotherm for PC/KC/PAAc and the Redlich–Peterson isotherm for MWCNTs@PC/KC/PAAc, both following a pseudo-second-order kinetics model. In addition, from AFM data, after MB removal, the height increased significantly from 322 nm for PC/KC/PAAc to 810 nm for MWCNTs@PC/KC/PAAc (0.175 wt%), indicating a substantially higher adsorption of MB by MWCNTs@PC/KC/PAAc.