Abstract:
Transition metal oxide nanoparticles have recently been linked to favourable properties that allow them to be used in microelectronics, water purification, energy storage, sensing, and biomedicine. This has resulted in the development of a number of methods for generating transition metal oxide nanoparticles that are both less expensive and more ecologically friendly in recent years. Documented procedures include using high temperatures and pressures, as well as volatile and caustic substances including sodium hydroxide, and diethylene glycol in the manufacture of zinc oxide (ZnO). Morula leaf extract was used in the synthesis of birnessite,ZnO, and copper oxide (CuO) nanoparticles in this study. The active morula agents are extracted using boiling water followed by hydrothermal treatment with the metal oxide precursors to synthesize the metal oxide nanoparticles. There were no other hazardous substances used apart from water which is considered to be green. X-ray diffraction (XRD) analysis showed that pure and crystalline structures of CuO and ZnO were fully formed after calcination at 350 ℃.birnessite structure was formed after hydrothermal treatment at 180 ℃ according to the XRD
data. Raman spectroscopy was used to determine the molecular functional groups of the
materials using the fingerprint regions on the spectra. CuO was determined by the doublet peak between 200 and 400 cm-1, birnessite by the singlet peak between 600 and 700 cm-1 and ZnO by the characteristic peaks at 318, 429 and 566 cm-1. Scanning electron microscopy (SEM) and Brunauer–Emmet–Teller (BET) analysis were used to analyze the structural morphology and the adsorptive behaviour of the materials, respectively. Platelets were discovered in CuO, while birnessite and ZnO featured flower-like and nanorod-like structures, respectively. All three materials were discovered to have larger surface areas, 26.8 m2/g in the case of CuO, 31.6 m2/g for birnessite and 21.29 m2/g for ZnO. Flaws such as rough particles and cracks in the structure of the material were also discovered, which aided their respective uses substantially. CuO and birnessite were applied in the adsorption of dyes. Two different adsorption isotherms (Freundlich and Langmuir) were used to probe the activity of these metal oxides in the adsorption of dye. The Langmuir constant (RL) values obtained are in the range of 0–1, showing that both dyes in the mixture i.e., methylene blue (MB) and rhodamine 6G (R6G), adsorb well on CuO and birnessite in an adsorption process. Furthermore, the values of n which is a constant
vii which depends upon the nature of adsorbent and the gas at a given temperature, exceed one, indicating that metal oxides are effective adsorbents for both dyes. CuO and birnessite have a maximum adsorptive efficiency of 78 and 99 %, respectively.
In the photodegradation of the combined dyes, ZnO was used. Its degradation efficiency was 99%. The degrading efficiency increased as the catalyst amount, contact time, and reaction temperature were increased.
