تحضير وتشخيص المركبات النانوية Nb2O5 /CdS ودراسة الامتزاز وفعالية المحفز الضوئي للايونات الفلزية الانتقالية == Synthesis, Characterization of Nb2O5 /CdS Nano Composites, and Study Sorption and Photocatalytic Activity of Transition Metal Ions
Author name:
زينة طالب عمران
Supervisor name:
ندى يحيى فيروز
General topic:
Chemistry
Specific topic:
Chemistry
Degree:
Master
University:
University of Babylon - College Of Science
Language:
English
University location:
Babylon
First pages:
25T1551 - p.pdf
Abstract:
This study includes preparation of nano composite catalyst Nb2O5\CdS at various ratios by using wet commixing method with changed calcination temperature 200, 500 and 800 ⁰C .The catalysts were characterized using X - rays diffraction (XRD), Fourier Transform Infrared (FTIR), Scanning Electron Microscopy SEM and Atomic Force Microscopy (AFM). Then used all of these ratio that calcinated at various temperature in degradation procedure of both Co (II) and Cu (II) from their aqueous solutions. It was found that the catalyst with a ratio of ( 0.85 : 0.15) and (0.75 : 0.25), which was calcinated at 800⁰C it’s the best ratios for Co(II) and Cu(II). Removal of Co (II) was examined after optimization of removal conditions, for example, mass of catalyst , pH of mixture, effect of temperature ,effect of concentration of Co (II) and effect of addition hydrogen peroxide . The best conditions for this case were pH=4, 0.1 g , 500ppm and temperature equal to30ºC, 0.1M of H2O2. Activation energy was calculated using Arrhenius plot and it was 26.28 kJ/mol.Study adsorption of Co(II) was examined after ideal of conditions for example effect of mass of catalyst , effect of concentration of Co (II), pH of mixture, effect of temperature . The ideal conditions for this case were 0.1 g , 500ppm , temperature equal to30ºC, pH=4, and. Activation energy was calculated using Arrhenius plot and it was 8.363 kJ.mol - 1Kinetics of this procedure was investigated and it was fitted with the pseudo first order kinetics. In addition to that, adsorption isotherms for this process were applied for both Langmuir and Freundlich adsorption isotherms. The obtained results presented that it was agreedIIwith Freundlich adsorption model. Study thermodynamic parameters results exhibited that the negative values of ΔG( - 2.346, - 3.571 , - 4.697 , - 5.259 kJ/mol ) for temperature (15 ,20 ,23 ,30 )oC and the positive ΔH (+55.66kJ/mol) and ΔS (+0.201kJ/mol K) .Removal of Cu (II) was examined after ideal conditions such as mass of catalyst , pH of mixture, effect of temperature , effect of concentration of Cu (II) and effect of addition hydrogen peroxide . The ideal conditions for this case were 0.05 g, 500ppm, 30ºC , pH=3 ,0.1M of H2O2. Activation energy was calculated using Arrhenius plot and it was 9.814 kJ.mol - 1.Study adsorption of Cu (II) was investigated after best of conditions for example effect mass of catalyst , effect of concentration of Co (II),pH of mixture, effect of temperature . The ideal conditions for this case were 0.15 g , 500ppm ,30ºC, and pH=3. Activation energy was calculated using Arrhenius plot and it was 8.866 kJ.mol - 1Kinetics of this process was studied and it was fitted with the pseudo first order kinetics. In addition to that, adsorption isotherms for this procedure were applied for both Langmuir and Freundlich adsorption isotherms. The obtained results presented that it was agreed with Freundlich adsorption model. Study thermodynamic parameters results exhibited that the negative values of ΔG( - 3.110, - 3.919, - 5.785 , - 8.300kJ/mol ) for temperature(15 ,20 ,23 ,30) oC and the positive ΔH (+58.42kJ/mol ) and ΔS (+0.213 kJ/mol K ) .
