Abstract:
Contamination of water resources by methylene blue dye has become a source of environmental
concern because of its toxicity thus causing significant harm to human organs and having an
impact on aquatic lives. Although Zinc Oxide nanoparticles synthesized by chemical and
physical methods have been developed for the removal of methylene blue dye wastewater by
adsorption method, Zinc Oxide nanoparticles lose reactivity towards the adsorbate, posing
toxicity to the environment, instability, and agglomeration problematic. Hence, surface modified;
green synthesized Zinc Oxide nanoparticles are alternative adsorbent, which form stable and
alleviate agglomeration in the Zinc Oxide nanoparticles synthesis for methylene blue dye
removal are required. The emphasis of this thesis is on the green synthesis, characterization, and
application of Zinc oxide teff straw assisted nanoparticles for the removal of methylene blue dye
from textile wastewater.Teff straw-assisted Zinc Oxide nanoparticles were synthesized by
reduction of Zinc nitrate hexahydrate solution using neem leaf extract as a capping agent. The
physicochemical properties of Teff straw assisted Zinc Oxide nanoparticles were characterized
using, X-ray diffraction and Fourier transform-infrared spectroscopy, analysis confirmed that
the surface of Zinc oxide nanoparticles was efficiently functionalized. The X-ray diffraction
analysis revealed the presence of Zinc oxide in the synthesized Teff straw-assisted Zinc Oxide
nanoparticles with an average crystalline size of 27.196 nm. Series adsorption experiments were
conducted to examine the removal efficiency of methylene blue dye on Teff straw-assisted Zinc
Oxide nanoparticles and the effect of various adsorption parameters from Textile Wastewaters.
It was found that pH, the dose of Teff straw assisted Zinc Oxide nanoparticles, contact time and
initial concentration affects the removal of methylene blue dye. A response surface methodology
with the central composite design was used for the optimization of removal efficiency of
methylene blue dye onto the adsorbent’s surface. The optimal conditions selected using the
design tool were 6.904 pH, 68.489 mg/L initial methylene blue dye concentration,0.265 g dosage
of Teff straw assisted Zinc Oxide nanoparticles, and 77.873 min contact time providing a
predicted value of 99.769 % removal efficiency and this was adequately fit into the Freundlich
isotherm model with correlation coefficient of 0.99. Also, the water quality parameters in real
textile wastewater were determined and its removal efficiency was 92.5%
