Ragaa Elsayed Alazabawy

@azhar.edu.eg

Assistant Professor of Physical Chemistry, Department of Chemistry, Faculty of Science for Girls, Cairo, Al-Azhar University
Al-Azhar University

Ragaa Elsayed Alazabawy


                  Download Compact PDF  
https://researchid.co/dr.ragaaelsayed

RESEARCH, TEACHING, or OTHER INTERESTS

Chemistry
6

Scopus Publications

Scopus Publications

  • Comparative Study between a Copolymer Based on Oleic Acid and Its Nanohybrid for Improving the Cold Flow Properties of Diesel Fuel
    Abeer A. El-Segaey, Ragaa E. El-Azabawy, Hoda A Mohammed, Hussin I. Al-Shafey, Rasha S. Kamal
    ACS Omega, 2023
    The as-synthesized copolymer based on the prepared monomers and its nanohybrid were used for improving the cold flow of diesel fuel that has a vital role in meeting energy needs. The copolymer (AE) was created using the prepared monomers, by free radical solution polymerization of the prepared hexadecylmaleamide and octyloleate ester, and the polymer nanohybrid (NH) was created by emulsion polymerization of the same monomers with 1% nano-SiO2. The chemical structures of the copolymer and its nanohybrid were proved by Fourier transform infrared spectroscopy (FTIR), 1H NMR, dynamic light scattering (DLS), and transmission electron microscopy (TEM). Through exploring the effect of the nanohybrid, before and after adding the dosage of the additives to the diesel fuel, the pour point temperature (PPT), rheological characteristics, and viscosity index were measured. The data were the best for the nanohybrid; the PPT decreased from −3 to −36 °C upon adding 10,000 ppm nanohybrid but decreased from −3 to −30 °C for 10,000 ppm copolymer. In addition, the efficiency of the additives was proved by viscosity–shear rate and shear rate–shear stress curves to give the apparent viscosity, which decreased from 124 cP for the blank to 15.74 and 12.8 cP for AE and NH, respectively; also, the yield stress decreased from 576 D/Cm2 for the blank to 541.44 and 477.9 D/Cm2 for AE and NH, respectively, at room temperature. The viscosity index increased from 116 for the blank to 119 and 121 for the copolymer and the nanohybrid, respectively. Polarizing optical microscopy was performed to show more tiny and separated wax upon adding the additives. The findings showed that delayed crystal precipitation and altered crystal shape with the NH and AE greatly reduced low-temperature viscosity and enhanced the cold flow characteristics of the diesel fuel.
  • Study the Effect of Biowaste-Based Natural Dyes on Cationic Surfactant
    Asmaa Ahmed Moussa, alshimaa gomaa, Ragaa El-Azabawy, El-Bayaa, A.
    Egyptian Journal of Chemistry, 2022
    In this work, UV-Vis spectra are used to observe the absorption spectra of aqueous extraction of Beetroot peel and Henna leaves dyes, in presence and absence of cationic surfactant. The maximum absorbance in Beetroot appears to be at 535 in both cases only the intensity of the peak change after addition of surfactant. In contrast with the Beetroot, henna dye showed maximum wavelength changed from 435 nm to 347 nm after the addition of surfactant. Fourier Transform Infrared Spectroscopy (FTIR) identifies the functional groups of those dyes and the change of adding a surfactant to these dyes is also discussed. For both dyes, there is no change of the peaks, only showing intensity change in the presence of surfactant. Mass spectroscopy showed the presence of betalain as the main component in the Beetroot extract, also proved the presence of lawsone in the Henna extract. The conductance at different concentrations for the extracted dyes has been measured. Also, the effect of temperatures and pH had recorded. The results showed the highest conductance for extracted dyes were at the highest concentration (10% and 1.5%) for (2214.5 and 50.367) μScm -1 for Beetroot and henna respectively. The CMC of the extracted dyes at room temperature was determined by surface tension (  ) measurements in the presence and absence of the cationic surfactant. The result shows a decrease in the value in the presence of surfactant than that in its absence as it changes from (50x10 3 to 40 x10 3 ) mg/l and (20x10 3 to 15x10 3 ) mg/l for Beetroot and Henna respectively.
  • Valorization Beetroot Waste for Eco-Friendly Extraction of Natural Dye for Textile and Food Applications
    Asmaa Ahmed Moussa, alshimaa gomaa, Ragaa El-Azabawy, El-Bayaa A.
    Egyptian Journal of Chemistry, 2022
  • Efficient removal of methylene blue dye from aqueous media using Fe/Si, Cr/Si, Ni/Si, and Zn/Si amorphous novel adsorbents
    Ehab A. Abdelrahman, R.M. Hegazey, Ragaa E. El-Azabawy
    Journal of Materials Research and Technology, 2019
  • Synthesis and Characterization of Magnetite-Alginate Nanoparticles for Enhancement of Nickel and Cobalt Ion Adsorption from Wastewater
    Omnia A. A. El-Shamy, Ragaa E. El-Azabawy, Olfat. E. El-Azabawy
    Journal of Nanomaterials, 2019
    Superparamagnetic magnetite-alginate nanoparticles (M-AlgNPs) were synthesized utilizing a coprecipitation method. Then, the prepared M-AlgNPs were characterized via Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction spectroscopy (XRD) to affirm the formation and the crystallinity of this composite. In addition, the surface morphology of the prepared nanoparticles was inspected by transmission electron microscopy (TEM) which revealed well-dispersed nanoparticles of Fe3O4 into alginate. The adsorption characteristics of the synthesized nanoparticles for removing Ni+2 and Co+2 from wastewater were evaluated via atomic absorption measurements (AAS). The elimination efficiency of the M-AlgNPs was detected at pH=7 in 100 ppm (initial concentration) of Ni+2 and Co+2, separately. The M-AlgNPs provided the maximum equilibrium uptake percentage for Ni+2 and Co+2 of 97.88 and 95.01%, respectively. The adsorption of Ni+2 and Co+2 onto the M-AlgNP surface was found to fit the Langmuir model with R2 values higher than that obtained from the Freundlich model for both metal ions. Moreover, RL “separating factor” for the adsorption process was assessed and found to be less than unity; this expresses the higher ability of the investigated metal ions to be adsorbed onto the M-AlgNP surface. The adsorption method was discovered to be pH-dependent and well-suited to the isothermal equations of Langmuir and Freundlich. For regeneration studies, M-AlgNPs have been investigated and results confirmed that it could be reused with effective sorption capacity over three cycles.
  • Investigation of adsorption and inhibitive effect of acid red GRE (183) dye on the corrosion of carbon steel in hydrochloric acid media
    M. Abd El-raouf, Olfat E. El-Azabawy, R.E. El-Azabawy
    Egyptian Journal of Petroleum, 2015