tamanna pinky | Jahangirnagar University (original) (raw)
Address: Dhaka, Dhaka Division, Bangladesh
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Photodegradation of methyl orange spectrum in aqueous ZnO suspension by UV irradiation has shown ... more 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 photocatalyst 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...
Asian Journal of Applied Chemistry Research
The contaminations and exposures of some metals recognized as a risk to human health owing to con... more The contaminations and exposures of some metals recognized as a risk to human health owing to consumption of components through water and atmosphere. Nine composite samples consist of five completely different waters and four soils were collected from the various places of Gopalgonj, Bangladesh. These were digestible and examined, during this study. Quantifications of various metals from the composite specimens were created by Atomic Absorption spectrophotometer strategies (AAS) against commonplace activity plot. The frequency of metals were determined within the order of soil > waters. Concentration of the following metals Cd, Cr, Cu, Fe, Mn, Zn, Ca and Mg for soil samples is more than that of water samples. With increasing concentrations of Co, Ni, Na and K were determined in waters compared to soils. Very low concentrations of metals were found from water samples. The Fe, Cr, Ni, Na and Mn concentrations exceeded the approved permissible levels in soils specimens and rests wer...
Journal of Organometallic Chemistry
The reaction of thiosaccharin (tsacH) with the triosmium cluster [Os3(CO)10(NCMe)2] furnishes the... more The reaction of thiosaccharin (tsacH) with the triosmium cluster [Os3(CO)10(NCMe)2] furnishes the decacarbonyl isomers [HOs3(CO)10(μ-S-tsac)] (1) and [HOs3(CO)10(μ-N,S-1,3-tsac)] (2) in a 3:1 ratio at room temperature. These isomers differ by the coordination mode displayed by tsac ligand. The tsac moiety functions as an edge-bridging ligand via the sulfur atom in 1 while in 2 the bridging of adjacent osmium centers is achieved through the sulfur and nitrogen groups. The ancillary hydride in both products shares the Os-Os edge that is bridged by the heterocyclic ligand. Heating 1 at 80 °C affords 2 and demonstrates that the former cluster is the product of kinetic control. The conversion of 1 2 has been investigated by DFT and the isomerization pathway elucidated. The DFT calculations confirm cluster 2 as the thermodynamically preferred isomer in this pair of products. Thermolysis of 2 in refluxing toluene affords the hexanuclear cluster [H2Os6(CO)17(μ-C,N-1,2-C6H4CNSO2)2(μ3-S)(μ4-S)] (3) via carbon-sulfur bond scission and subsequent capture of the extruded sulfur by the cluster core. The molecular structures for the three new clusters have been determined by single-crystal X-ray diffraction analyses.
Photodegradation of methyl orange spectrum in aqueous ZnO suspension by UV irradiation has shown ... more 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 photocatalyst 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...
Asian Journal of Applied Chemistry Research
The contaminations and exposures of some metals recognized as a risk to human health owing to con... more The contaminations and exposures of some metals recognized as a risk to human health owing to consumption of components through water and atmosphere. Nine composite samples consist of five completely different waters and four soils were collected from the various places of Gopalgonj, Bangladesh. These were digestible and examined, during this study. Quantifications of various metals from the composite specimens were created by Atomic Absorption spectrophotometer strategies (AAS) against commonplace activity plot. The frequency of metals were determined within the order of soil > waters. Concentration of the following metals Cd, Cr, Cu, Fe, Mn, Zn, Ca and Mg for soil samples is more than that of water samples. With increasing concentrations of Co, Ni, Na and K were determined in waters compared to soils. Very low concentrations of metals were found from water samples. The Fe, Cr, Ni, Na and Mn concentrations exceeded the approved permissible levels in soils specimens and rests wer...
Journal of Organometallic Chemistry
The reaction of thiosaccharin (tsacH) with the triosmium cluster [Os3(CO)10(NCMe)2] furnishes the... more The reaction of thiosaccharin (tsacH) with the triosmium cluster [Os3(CO)10(NCMe)2] furnishes the decacarbonyl isomers [HOs3(CO)10(μ-S-tsac)] (1) and [HOs3(CO)10(μ-N,S-1,3-tsac)] (2) in a 3:1 ratio at room temperature. These isomers differ by the coordination mode displayed by tsac ligand. The tsac moiety functions as an edge-bridging ligand via the sulfur atom in 1 while in 2 the bridging of adjacent osmium centers is achieved through the sulfur and nitrogen groups. The ancillary hydride in both products shares the Os-Os edge that is bridged by the heterocyclic ligand. Heating 1 at 80 °C affords 2 and demonstrates that the former cluster is the product of kinetic control. The conversion of 1 2 has been investigated by DFT and the isomerization pathway elucidated. The DFT calculations confirm cluster 2 as the thermodynamically preferred isomer in this pair of products. Thermolysis of 2 in refluxing toluene affords the hexanuclear cluster [H2Os6(CO)17(μ-C,N-1,2-C6H4CNSO2)2(μ3-S)(μ4-S)] (3) via carbon-sulfur bond scission and subsequent capture of the extruded sulfur by the cluster core. The molecular structures for the three new clusters have been determined by single-crystal X-ray diffraction analyses.