Photodegradation of methyl orange spectrum in aqueous ZnO suspension by UV irradiation has shown time-dependent UV photodegradation. Methyl orange shows absorption peaks at 463 nm in the visible region. The rate of decolourization was recorded with respect to the change in the intensity of absorption peaks at 463 nm. The absorbance decreased with time and finally disappeared as the irradiation was scattered with time. It is seen that about 40% of dye was degraded after 30 minutes whereas about 60% of dye degraded after hours. The effect of photo-catalyst concentration on the photo-degradation rate of the methyl orange dye was investigated by employing different concentrations of ZnO from 0.2 to 2.0 g/100 mL with dye concentration 2 mg/100 mL at normal pH of methyl orange solution. The highest decrease in the concentration of methyl orange solution was observed for the ZnO of 1.4 g/mL during 60 minutes of irradiation. After optimizing the catalyst concentration of ZnO suspension (1.4g/100mL), the photocatalytic degradation methyl orange solution was carried out by varying the initial concentration of dye from 6mg/100mL to 10mg/100mL in order to assess the appropriate concentration of the dye required for maximum degradation. The percentage of degradation of methyl orange is scattered with an increase in dye concentration. In the case of 7mg/100mL of MO solution about 68% of degradation was found after 60 minutes. The highest degradation of methyl orange is 64.458 which were obtained at pH 7.
Metal complexes have been synthesized by the reaction of thiophene-2- aldehyde thiosemicarbazone with Cu(OAc)2 and Ni(OAc)2. The thiosemicarbazone coordinates to metal ions through the thionic sulfur and the azomethine nitrogen. The thiosemicarbazone is obtained by the reaction of thiosemicarbazide with thiophene-2- aldehyde. The identities of these compounds have been elucidated by IR and ESI-MS spectroscopic methods and elemental analyses. Thermogravimetric analysis data indicates that the metal complexes are thermally stable. The antibacterial activity of the synthesized compounds are tested by the disc diffusion assay against Gram-positive and Gram-negative bacteria. The antibacterial screening activity revealed that complexes showed moderate activity against tested bacterial strains and slightly higher compared to the ligand, L.
New Schiff base ligand was synthesis via a condensation of the ligands in methanol. The Schiff base were synthesized in 1:2 molar ratio reactions. The complexes [Mn(HL1)2Cl, Cu(HL1)2 and Ni(HL1)2Cl] have been characterized on the basis of FTIR, electronic spectra, melting points/decomposition temperature, solubility and molar conductance. The in-vitro antibacterial activity of the complexes was tested using two gram-negative (Escherichia coli and Salmonella typhimurium) and two gram-positive (Staphylococcus pyogenes and Staphylococcus aureus) bacterial strains. The IR bands of Schiff bases showed a broad-band at 3317 cm-1. The strong bands at 1590 cm-1 range was assigned to v(C=N) vibration which reveals coordination of the carbonyl group of the aldehyde and the amine group of the 3-aminophenol and salicylaldehyde which ascertain the formation of the azomethine bond. The ⱱ(C=N) observed at 1603, 1591 and 1591 cm-1 range in the spectra of the complexes showed a shift to higher frequencies in all the complexes. These show the participation of the azomethine nitrogen in the coordination. The bands at 690, 512 and 512 cm-1were assigned to (M–N) and the bands at 538, 461 and 461 cm-1 were assigned to (M–O). The electronic spectral data of the complexes suggest an octahedral and tetrahedral geometry for all the complexes. The molar conductivity indicates that the synthesized complexes are all non-electrolytes and soluble in protic solvent such as methanol and ethanol. The synthesized metal complexes showed improved broad-spectrum antimicrobial activity against gram-positive and gram-negative bacteria better than the Schiff base. Thus, the complexes should be considered as possible lead compounds to be developed into antibiotics against the tested bacterial strains E. coli, S. typhimurium, S. aureus and S. pyrogens.
This work focused on the removal of methylene blue dye from aqueous solution using modified clay from Ngbo clay deposit in Ebonyi State, Nigeria. The clay was modified to zeolite by alkaline activation at a high temperature. Characterization of the clay was used to determine the properties of the clay. Batch experimental study was employed to determine the effects of process variables. Different isotherm and kinetic models were used to describe the adsorption process. The result showed that aluminium and iron were the major constituents of the clay. Percentage removal of the dye was significantly dependent on temperature, dosage and time. Maximum percentage adsorption of about 97% has been obtained. Pseudo second order best described the kinetic of the adsorption while Freundlich and Henry isotherm models were best in describing the adsorption isotherm. The study has shown synthesised zeolite as an effective, efficient, benign and cheap alternative sorbent for the adsorption of methylene blue from solutions.
Major problems encountered in industries, science and engineering is corrosion failure. The gravimetric, the electrochemical impedance spectroscopy (EIS) technique and Vickers hardness test were employed in investigating the anti-corrosion process of Aluminum alloy in acidic environment (0.5 M HCl solution) using Epiphyllum oxypetalum leaf extract. The leaf extraction was prepared using reflux set-up. Addition of the leaf extract in the corrosive media significantly reduced the mass loss and the corrosion (damage) rate. The inhibition efficiency increased linearly with the inhibitor concentration with a peak value of 89% for gravimetric technique and 87% for EIS technique, but slightly reduced with temperature rise. The charge-transfer resistance, Rct increased linearly with the increase in concentration of the inhibitor in the corrosive environment. The Vickers’s microindentation hardness test investigated revealed a preservation of the indentation value of the AA5052 exposed to inhibitive environment compared with those exposed to uninhibited environment. Surface screening was conducted and examined the surface morphology of the metals before, and after exposure to the various inhibitive solution. The experimental data obeyed Langmuir adsorption isotherm. Thermodynamic parameters (heat of adsorption, ∆H*, activation energy, Ea, entropy, ∆S* and Gibb’s free energy, ∆Gads) were evaluated through the Eying and Arrhenius plots. Upon the addition of the inhibitor, ∆H and Ea increased while the ∆S* decreased.