Departments of Chemistry

Permanent URI for this collectionhttps://etd.hu.edu.et/handle/123456789/97

Browse

Filters

20242

Settings

Has files: YesSubject: search.filters.subject.Methylene blue

Search Results

Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    BIOSYNTHESIZED NITROGEN-ZINC-CODOPED COPPER OXIDE NANOPARTICLES FOR PHOTOCATALYTIC DEGRADATION OF METHYLENE BLUE
    (HAWASSA UNIVERSITY, 2024-06) YOHANNES SHUKA JARA
    Herein, nitrogen-zinc-codoped copper nanoparticles (N-Zn-CuO NPs) was successfully synthesized by using Pycnostachys Abyssinica Fresen plant leaf extract as a bioreducing and capping agent for the photocatalytic degradation of methylene blue under natural sunlight irradiation. Additionally, pure CuO NPs, N-CuO NPs, and Zn-CuO NPs were also biosynthesized for comparison. Characterization techniques of UV-Vis, XRD, SEM, FT-IR revealed that N-Zn-codoping narrowed the band gap (1.72 to1.07 eV), reduced the crystallite size (25 to11.23 nm), distortion of monoclinic crystal lattice (rhombus and diamond like shape with an average diameter of 2.25 µm to irregular shape with an average size of 2.75 µm), and towards redshift of the Cu-O characteristic peaks (617 to 529 cm-1 ) of CuO NPs, respectively, confirmed the successful incorporation of dopants into CuO NPs. The effects of key parameters on the photocatalytic degradation efficiency of all biosynthesised NPs were investigated. The optimal conditions with maximum degradation for N-Zn-CuO NPs were determined to be 3% dopant concentration for both N and Zn, 120 mg of photocatalyst dosage, pH of solution at 11, 20 ppm of Initial dye concentration and 30 minutes of reaction time. Photocatalytic activity towards methylene blue (MB) dye degradation under 30 minutes exposure to sunlight was 99.75% for N-ZnCuO NPs, outperforming pure CuO NPs (95.76%), N-CuO NPs (97.93%), and Zn-CuO NPs (98.26%) under optimal conditions. The enhanced photocatalytic performance of NZn-CuO NPs is attributed to their tailored optical properties, leading to improved charge separation and reduced recombination. Kinetic studies revealed a strong fit (R2=0.99799) with the BMG kinetic model for N-Zn-CuO NPs, indicating surface-mediated degradation of MB. Furthermore, the nanocatalysts exhibited excellent reusability and stability over four cycles. This finding highlights the potential of biosynthesized N-Zn-CuO NPs as highly efficient, simple, eco-friendly and sustainable solutions for the degradation organic pollutants.
  • No Thumbnail Available
    Item
    REMOVAL OF METHYLENE BLUE DYES FROMAQUEOS SOLUTIONBYUSING ACTIVATED CARBON PREPARED FROMSTEMPARTOFCROTON MACROSTACHYUS (BISANA)
    (Hawassa University, 2024-10) HUSSIEN MAMA MIDASSO
    In this study activated carbon was prepared from Stem part of Croton macrostachyus andutilizedas adsorbent to study its adsorption ef iciency towards removal of Methylene blue dye fromaqueoussolution. The AC was prepared by acid treatment and calcinated in muf le furnace at dif erenttemperature ranging from 400 0C to 700 0C. The prepared AC was characterized by usingFT-IRandscanning electron microscope (SEM).FT-IR results showed that dif erent functional groupslikehydroxyl, aldehydes, and carbon-carbon double bond functional groups were observed at dif erentwave numbers. The amount of MB dyes adsorbed was determined using UV-Vis spectrometeryat itsλ max of 664 nm. It was found that the adsorption of MB on adsorbent obeys the Langmuiradsorption isotherms. The Values of the equilibrium parameter ‘RL’ from the Langmuir isothermwas0.040. These results confirmed that the adsorption process of MB dye on the preparedActivatedcarbon is favorable.The ef ects of some working parameters like pH, dye initial concentration, temperature and contact time on the adsorption of MB dyes were also studied. The optimumconditions were maximum removal ef iciency occur was at dose of 0.1 gram, initial concentrationof10 ppm, contact time of 90 minutes, pH of 8 and temperature of 45 0C. The dye adsorptionwas foundto decrease with increasing initial dye concentration and the percentage removal of the dyeandtheamount adsorbed on the surface of the adsorbent both showed significant increase with increaseintemperature up to 45 oC. The ef ect of contact time on the percent removal of MBdyeshowedincreasing trend as the reaction time increase. It was observed that the pseudo-second-order kineticmodel fits better with good correlation coef icient and the equilibrium data fitted well withlangmuirmodel.