Adama University

About: Adama University is a education organization based out in Nazrēt, Ethiopia. It is known for research contribution in the topics: Population & Adsorption. The organization has 840 authors who have published 1010 publications receiving 5547 citations. The organization is also known as: Adama Science and Technology University & ቴክኖሎጂ ዩኒቨርሲቲ, አዳማ ሳይንስና ቴክኖሎጂ ዩኒቨርሲቲ.

Synthesis of Poly(vinyl alcohol)-Aided ZnO/Mn2O3 Nanocomposites for Acid Orange-8 Dye Degradation: Mechanism and Antibacterial Activity.

Abstract: Zinc oxide is one of the novel metal oxides utilized for diverse applications. The sol-gel and unintended self-propagation procedures were applied to synthesize the porous and high surface area ZnO-based metal oxide nanocomposite. The p-type manganese(III) oxide was successfully coupled with n-type ZnO. The physical property characterization results revealed the surface area, porosity, and charge transfer capability improvement on the poly(vinyl alcohol) (PVA)-aided binary nanocomposite (PVA-ZnO/Mn2O3), compared to ZnO. The XRD patterns and TEM image analysis validated the nanometer size range for the materials (15-60 nm). The SEM micrographs and BET spectral details have confirmed the porous nature of the PVA-ZnO/Mn2O3 nanocomposite. The supporting results were obtained from the HRTEM (IFFT) and SAED pattern analyses. The EDX and HRTEM analyses were used for the confirmation of elemental composition and reality of the PVA-ZnO/Mn2O3 composite, respectively. The presence of the improved charge transfer property for PVA-ZnO/Mn2O3, compared to ZnO, was evidenced from acid orange-8 dye degradation. The highest zone of inhibition (14 mm) was recorded on Escherichia coli bacteria for the uncalcined PVA-ZnO/Mn2O3 nanocomposite compared to PVA, yet, less zone of inhibition compared to the calcined PVA-ZnO/Mn2O3 nanocomposite. The authors recommend the formation of the couple between metal oxides by electrochemical technique analyses as a future work.

Calcium oxide nanoparticles synthesis from hen eggshells for removal of lead (Pb(II)) from aqueous solution

Abstract: Lead is an important industrial heavy metal used in various production industries. Remediation of Lead poisoned areas has both economical and technological challenges, as conventional and techniques are very expensive to apply for wastewater treatment and its operation is difficult. The adsorption method could solve the problem using sol-gel-based synthesized adsorbent since it is environmentally friendly with high-quality product produced. In the present study, the application of synthesized calcium oxide nanoparticles from hen eggshells for the removal of lead ions from aqueous solutions is what was investigated. Characterization of the adsorbent like proximate analysis, particle density, bulk density, porosity, point of zero charges, Fourier transform infrared radiation spectroscope, X-ray diffraction, specific surface area, thermal gravimetric analysis, and scanning electron microscopy was done before batch adsorption experiments. X-ray diffraction revealed that the size of synthesized calcium oxide nanoparticles was 24.34 nm and the specific surface area was 77.4m2/g. The removal of divalent lead ions from aqueous solutions was optimized by using response surface methodology. The optimum percent removal of lead (99.07) has resulted at initial concentration 75.46 ppm, pH 6.94, adsorbent dose 0.838 g, and contact time 101.97 min. The experimental removal efficiency (98.86%) agreed very well with the predicted one (99.07%), showing the suitability of the model used and the success of response surface methodology in optimizing of removal of Pb (II) ions from aqueous solutions. The lead ions removal was well fitted into the Langmuir isotherm model with correlation coefficients of 0.9963. The adsorption kinetic data were well fitted with the pseudo-second-order model with a correlation coefficient of 0.9982. The pseudo-second-order model was the rate-limiting step in the lead (II) ions adsorption process onto CaO NPs. Based on the obtained results, the calcium oxide nanoparticles prepared from eggshell have a good capacity for the removal of the lead ions from the aqueous solutions.

Spherical nanoflower-like bimetallic (Mo,Ni)(S,O)3-x sulfo-oxide catalysts for efficient hydrogen evolution under visible light

Abstract: Photocatalytic H2O splitting by sulfide-based materials is a great challenge, because of the poor resilience of such materials against hole oxidation. Although sulfide ion of catalyst negatively shifts the valence band-edge relative to its oxide ion, the instability of sulfide ions during H2O oxidation is a critical obstacle to simultaneous evolution of H2 and O2. Here, active, stable, and spherical nanoflower-like bimetal (Mo,Ni)(S,O)3-x sulfo-oxide catalysts with a band gap of ∼2.1 eV and different concentrations of oxygen vacancy defects were synthesized for H2O splitting. (Mo,Ni)(S,O)3-x of 25 mg with a suitable amount of oxygen vacancy defects could evolve 587.5 μmol/h H2 under visible-light irradiation. This work demonstrated an example of converting an oxidation photocatalyst into a reduction one. Microstructure analysis showed that surface oxygen vacancy defects and the multiple-valence charges in Ni and Mo not only promoted effective separation, interface transfer, and reactions of photo-carriers but also reduced the charge build-up to avoid photo-corrosion during photocatalytic water decomposition.