ABSTRACT
The effect of surfactant and dopant on the properties of zinc oxide nanoparticles were studied by preparing polyethylene glycol (PEG) capped ZnO and tungsten doped PEG capped ZnO nanoparticles via the electrochemical method. These nanoparticles were characterized using X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Ultraviolet Diffuse Reflection Spectroscopy (UV-DRS), Scanning Electron Microscopy (SEM) and Electron Dispersive Analysis of X Rays (EDAX). The photocatalytic degradation of malachite green dye using these nanoparticles was studied under visible light. The effects of various reaction parameters like dye concentration, catalyst concentration, pH and time were studied to optimize the photodegradation reaction. Reusability of these nanoparticles was studied and no significant change was observed in the degradation efficiency of PEG capped ZnO till the fourth cycle, while there was a gradual decrease in the degradation efficiency of tungsten doped PEG capped ZnO. Langmuir- Hinshelwood kinetic model well describes the photodegradation capacity and the degradation of malachite green follows pseudo-first order kinetics.Photocatalytic studies reveal that PEG capping increases the degradation properties of ZnO while tungsten doping decreases the extent of PEG capping and has a detrimental effect on the degradation properties of ZnO. The prepared nanoparticles exhibit significant antibacterial properties against gram-positive Bacillus cereus and gram-negative Escherichia coli bacterial strains by agar well diffusion method.
Subject(s)
Anti-Bacterial Agents/chemical synthesis , Metal Nanoparticles/chemistry , Polyethylene Glycols/chemistry , Zinc Oxide/chemistry , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/pharmacology , Bacillus cereus/drug effects , Catalysis , Coloring Agents/chemistry , Disk Diffusion Antimicrobial Tests , Electrochemical Techniques , Escherichia coli/drug effects , Hydrogen-Ion Concentration , Light , Metal Nanoparticles/toxicity , Microscopy, Electron, Scanning , Photolysis/drug effects , Photolysis/radiation effects , Spectrometry, X-Ray Emission , Spectroscopy, Fourier Transform Infrared , Tungsten/chemistry , X-Ray DiffractionABSTRACT
Nickel(II) reacts with N-ethyl-3-carbazolecarboxaldehyde-3-thiosemicarbazone (ECCT) and forms a yellow colored complex, which was extracted into n-butanol from sodium acetate and acetic acid buffer at pH 6.0. The absorbance value of the Ni(II)-ECCT complex was measured at different intervals of time at 400 nm, to ascertain the time stability of the complex. The extraction of the complex into the solvent was instantaneous and stable for more than 72 h. The system obeyed Beer's law in the concentration range of 1.2-5.6 microg ml(-1) of nickel(II), with an excellent linearity and a correlation coefficient of 0.999. The molar absorptivity and Sandell's sensitivity of the extracted species were found to be 1.114 x 10(4)L mol(-1)cm(-1) and 5.29 x 10(-3)microg cm(-2) at 400 nm, respectively. Hence, a detailed study of the extraction of nickel(II) with ECCT has been undertaken with a view to developing a rapid and sensitive extractive spectrophotometric method for the determination of nickel(II) when present alone or in the presence of diverse ions which are usually associated with nickel(II) in environmental matrices like soil and industrial effluents. Various standard alloy samples (CM 247 LC, IN 718, BCS 233, 266, 253 and 251) have been tested for the determination of nickel for the purpose of validation of the present method. The results of the proposed method are comparable with those from atomic absorption spectrometry and were found to be in good agreement.
