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Papers by Sudipta Chatterjee

Research paper thumbnail of Self-assembly of stable oligomeric and fibrillar aggregates of Aβ peptides relevant to Alzheimer's disease: morphology dependent Cu/heme toxicity and inhibition of PROS generation

Research paper thumbnail of Syntheses, characterization and X-ray crystal structures of hexa-coordinated monomeric and oxo-bridged dimeric Fe(III) compounds with salen-type Schiff bases

Research paper thumbnail of Heterometallic inorganic–organic frameworks of sodium–nickel(vanen): Cation–π interaction, trigonal dodecahedral Na+ and unprecedented heptadentate coordination mode of vanen2−

Research paper thumbnail of Electrocatalytic O 2 Reduction Reaction by Synthetic Analogues of Cytochrome P450 and Myoglobin: In-Situ Resonance Raman and Dynamic Electrochemistry Investigations

Inorganic Chemistry, 2013

Research paper thumbnail of Unique example of a trigonal dodecahedral Na+ in a compartmental Schiff base N,N′-(1,2-Phenylene)-bis(3-methoxysalicylideneimine)

Inorganic Chemistry Communications, 2011

Research paper thumbnail of Bis(acetonitrile)bis(acetylacetonato)ruthenium(iii) mediated chemical transformations of coordinated 2-methylthioanilide

Dalton Transactions, 2012

Research paper thumbnail of Self-assembly of stable oligomeric and fibrillar aggregates of Aβ peptides relevant to Alzheimer's disease: morphology dependent Cu/heme toxicity and inhibition of PROS generation

Research paper thumbnail of Syntheses, characterization and X-ray crystal structures of hexa-coordinated monomeric and oxo-bridged dimeric Fe(III) compounds with salen-type Schiff bases

Research paper thumbnail of Heterometallic inorganic–organic frameworks of sodium–nickel(vanen): Cation–π interaction, trigonal dodecahedral Na+ and unprecedented heptadentate coordination mode of vanen2−

Research paper thumbnail of Electrocatalytic O 2 Reduction Reaction by Synthetic Analogues of Cytochrome P450 and Myoglobin: In-Situ Resonance Raman and Dynamic Electrochemistry Investigations

Inorganic Chemistry, 2013

Research paper thumbnail of Unique example of a trigonal dodecahedral Na+ in a compartmental Schiff base N,N′-(1,2-Phenylene)-bis(3-methoxysalicylideneimine)

Inorganic Chemistry Communications, 2011

Research paper thumbnail of Bis(acetonitrile)bis(acetylacetonato)ruthenium(iii) mediated chemical transformations of coordinated 2-methylthioanilide

Dalton Transactions, 2012

Research paper thumbnail of Enhanced solubilization of phenanthrene in Triton X-100 solutions by the addition of small amounts of chitosan

Chemical Engineering Journal - CHEM ENG J, 2010

The performances of aqueous mixtures of the model nonionic surfactant Triton X-100 (TX100) and ch... more The performances of aqueous mixtures of the model nonionic surfactant Triton X-100 (TX100) and chitosan (CS) for the solubilization of the hydrophobic organic compound phenanthrene (PHE) were evaluated by varying mixture compositions. The addition of minute amounts of CS into TX100 solutions above the critical micelle concentration significantly increased PHE solubility. The PHE solubility was maximized at certain optimal concentrations of CS increasing in proportion to the TX100 concentrations, which were 2, 10, and 20 mg/L CS for 5, 10, and 20 g/L TX100, respectively. At each optimal concentration of CS, PHE solubility was increased by 46%, 39%, and 43% for the 5, 10, and 20 g/L TX100 solutions, respectively. The enhanced solubilization of PHE by the addition of CS to TX100 solutions may be attributable to multiple factors, such as an increase of micellar size and hydrophobicity as well as to the formation of variously configured micelle-polymer aggregates.

Research paper thumbnail of Adsorption of Congo Red from Aqueous Solutions Using Chitosan Hydrogel Beads Formed by Various Anionic Surfactants

Separation Science and Technology, 2011

The structural organization of chitosan hydrogel beads (CSBs) formed by various anionic surfactan... more The structural organization of chitosan hydrogel beads (CSBs) formed by various anionic surfactants, sodium dodecyl sulfate (SDS), sodium decyl sulfate (DS), dodecyl benzenesulfonic acid sodium salt (SDBS), and dioctyl sulfosuccinate sodium salt (DSS), and their applications as adsorbents for environmental purifications were investigated using Congo red (CR) as a model dye. The adsorption capacities of CSB as a function of

Research paper thumbnail of Mechanistic enzymology in non-aqueous media

Pure and Applied Chemistry, 2000

Research paper thumbnail of Effect of coagulant addition on the sedimentation of a surfactant-containing washing solution used for phenanthrene-contaminated soil

Korean Journal of Chemical Engineering, 2011

ABSTRACT The coagulation of soil particles from a soil-washing solution containing the nonionic s... more ABSTRACT The coagulation of soil particles from a soil-washing solution containing the nonionic surfactant Triton X-100 (TX100) was investigated using various coagulants, such as chitosan (CS), polyacrylamide (PAA), and polyaluminum chloride (PAC). Soil contaminated with phenanthrene (PHE) was washed with aqueous TX100 solutions at concentrations ranging from 0.1 to 20 g/L. The effectiveness of CS (5 mg/L) as a coagulant in the system was compared with PAA (50mg/L) and PAC (50 mg/L), and the results indicated that the system with CS exhibited a more effective separation of soil than those with PAA and PAC. The removal efficiency of PHE (R j =81.7%) and the selective separation factor (SSF=14.2) at 10 g/L TX100 were the highest for the system with CS (5 mg/L), indicating that the selection of CS as a coagulant in surfactant-mediated soil washing markedly improved both PHE removal and soil separation. Key wordsChitosan–Coagulation–Phenanthrene–Soil Washing–Surfactant

Research paper thumbnail of Kinetic analysis of the mechanism for subtilisin in essentially anhydrous organic solvents

Enzyme and Microbial Technology, 1993

Research paper thumbnail of Adsorption of a cationic dye, methylene blue, on to chitosan hydrogel beads generated by anionic surfactant gelation

Environmental Technology, 2011

Chitosan hydrogel beads (CSB) formed by sodium dodecyl sulphate (SDS) gelation were used for the ... more Chitosan hydrogel beads (CSB) formed by sodium dodecyl sulphate (SDS) gelation were used for the removal of a cationic dye, methylene blue (MB), from aqueous solutions. The adsorption capacity of chitosan beads (CB) formed by alkali gelation was low because of charge repulsions between the chitosan (CS) and the MB. The adsorption capacity of CSB (4 g/L SDS gelation) for MB (100 mg/L) was 129.44 mg/g, and it decreased significantly with increasing SDS concentration during gelation. This decrease was a result of increased density of the CSB membrane materials. The CSB membrane materials formed with the 4 g/L SDS gelation showed the highest volumetric adsorption capacity. The MB adsorption on to CB and CSB increased with increasing values for the initial pH of solution. Data from both CB and CSB showed good fit to Sips isotherm models, and the maximum adsorption capacity of CSB (226.24 mg/g) was higher than that of CB (99.01 mg/g).

Research paper thumbnail of Effect of chitosan addition on phenanthrene solubilization in anionic or cationic surfactant solutions

Desalination and Water Treatment, 2012

ABSTRACT The solubility of solid phenanthrene (PHE) powder in aqueous solutions of surfactant and... more ABSTRACT The solubility of solid phenanthrene (PHE) powder in aqueous solutions of surfactant and chitosan (CS) was evaluated by varying the composition of aqueous mixtures. Cetyltrimethyl ammoniumbromide (CTAB) and sodium dodecyl sulfate (SDS) were used as model cationic and anionic surfactants, respectively. CS at a particular concentration in the mixture especially above the CMC value of the anionic surfactant exhibited somewhat higher PHE solubility values than surfactant itself. CS (20 mg/l)-SDS (20 g/l) solution showed higher PHE solubility (422.05 mg/l) than that of 20 g/l SDS (377.92 mg/g). However, CS-CTAB did not show any additional enhancing effect on PHE solubilization, and CS (5 mg/l)-CTAB (10 g/l) solution showed almost similar PHE solubility (867.23 mg/l) of 10 g/l CTAB (865.25 mg/g). The maximum increase in absorbance value of a 20 ml CS solution (5, 20 and 100 mg/l) at 540 nm with stepwise addition of SDS (10 g/l) was found at a SDS concentration much less than its CMC value (2.33 g/l) in the mixture, indicating strong complex formation between CS and SDS because of oppositely charged molecules in the experimental conditions

Research paper thumbnail of Coagulation of soil suspensions containing nonionic or anionic surfactants using chitosan, polyacrylamide, and polyaluminium chloride

Chemosphere, 2009

Effective coagulation and separation of particles in a soil-washed solution is required for a suc... more Effective coagulation and separation of particles in a soil-washed solution is required for a successful soil washing process. The effectiveness of chitosan (CS), a polycationic biodegradable polymer, as a coagulant was compared to polyacrylamide (PAA) and polyaluminium chloride (PAC) for the coagulation of a soil suspension (5 gL(-1)). The effect of surfactants in the coagulation process was investigated using Triton X-100 (TX-100), a nonionic surfactant, and sodium dodecyl sulfate (SDS), an anionic surfactant. CS (5 mgL(-1)) removed 86% and 63% of the suspended soil in the presence of TX-100 (5 gL(-1)) and SDS (5 gL(-1)), respectively, after 30 min at a pH of 6. The results prove that coagulation in the presence of TX-100 is more effective than with SDS. CS was found to be more efficient compared to PAA and PAC under all coagulation conditions. The optimum concentration of CS required for maximum coagulation of soil suspension was 5 mgL(-1). PAA and PAC could not achieve the same degree soil removal as CS even after increasing their concentrations up to 50 mgL(-1). Maximum levels of 50% and 60% soil removal were achieved using PAA (50 mgL(-1)) and PAC (50 mgL(-1)), respectively, after 30 min from a 5 gL(-1) suspension containing TX-100 (5 gL(-1)). The soil coagulation process was found to decrease with an increase in the pH of the suspension, and maximum coagulation was achieved with an acidic pH.

Research paper thumbnail of Self-assembly of stable oligomeric and fibrillar aggregates of Aβ peptides relevant to Alzheimer's disease: morphology dependent Cu/heme toxicity and inhibition of PROS generation

Research paper thumbnail of Syntheses, characterization and X-ray crystal structures of hexa-coordinated monomeric and oxo-bridged dimeric Fe(III) compounds with salen-type Schiff bases

Research paper thumbnail of Heterometallic inorganic–organic frameworks of sodium–nickel(vanen): Cation–π interaction, trigonal dodecahedral Na+ and unprecedented heptadentate coordination mode of vanen2−

Research paper thumbnail of Electrocatalytic O 2 Reduction Reaction by Synthetic Analogues of Cytochrome P450 and Myoglobin: In-Situ Resonance Raman and Dynamic Electrochemistry Investigations

Inorganic Chemistry, 2013

Research paper thumbnail of Unique example of a trigonal dodecahedral Na+ in a compartmental Schiff base N,N′-(1,2-Phenylene)-bis(3-methoxysalicylideneimine)

Inorganic Chemistry Communications, 2011

Research paper thumbnail of Bis(acetonitrile)bis(acetylacetonato)ruthenium(iii) mediated chemical transformations of coordinated 2-methylthioanilide

Dalton Transactions, 2012

Research paper thumbnail of Self-assembly of stable oligomeric and fibrillar aggregates of Aβ peptides relevant to Alzheimer's disease: morphology dependent Cu/heme toxicity and inhibition of PROS generation

Research paper thumbnail of Syntheses, characterization and X-ray crystal structures of hexa-coordinated monomeric and oxo-bridged dimeric Fe(III) compounds with salen-type Schiff bases

Research paper thumbnail of Heterometallic inorganic–organic frameworks of sodium–nickel(vanen): Cation–π interaction, trigonal dodecahedral Na+ and unprecedented heptadentate coordination mode of vanen2−

Research paper thumbnail of Electrocatalytic O 2 Reduction Reaction by Synthetic Analogues of Cytochrome P450 and Myoglobin: In-Situ Resonance Raman and Dynamic Electrochemistry Investigations

Inorganic Chemistry, 2013

Research paper thumbnail of Unique example of a trigonal dodecahedral Na+ in a compartmental Schiff base N,N′-(1,2-Phenylene)-bis(3-methoxysalicylideneimine)

Inorganic Chemistry Communications, 2011

Research paper thumbnail of Bis(acetonitrile)bis(acetylacetonato)ruthenium(iii) mediated chemical transformations of coordinated 2-methylthioanilide

Dalton Transactions, 2012

Research paper thumbnail of Enhanced solubilization of phenanthrene in Triton X-100 solutions by the addition of small amounts of chitosan

Chemical Engineering Journal - CHEM ENG J, 2010

The performances of aqueous mixtures of the model nonionic surfactant Triton X-100 (TX100) and ch... more The performances of aqueous mixtures of the model nonionic surfactant Triton X-100 (TX100) and chitosan (CS) for the solubilization of the hydrophobic organic compound phenanthrene (PHE) were evaluated by varying mixture compositions. The addition of minute amounts of CS into TX100 solutions above the critical micelle concentration significantly increased PHE solubility. The PHE solubility was maximized at certain optimal concentrations of CS increasing in proportion to the TX100 concentrations, which were 2, 10, and 20 mg/L CS for 5, 10, and 20 g/L TX100, respectively. At each optimal concentration of CS, PHE solubility was increased by 46%, 39%, and 43% for the 5, 10, and 20 g/L TX100 solutions, respectively. The enhanced solubilization of PHE by the addition of CS to TX100 solutions may be attributable to multiple factors, such as an increase of micellar size and hydrophobicity as well as to the formation of variously configured micelle-polymer aggregates.

Research paper thumbnail of Adsorption of Congo Red from Aqueous Solutions Using Chitosan Hydrogel Beads Formed by Various Anionic Surfactants

Separation Science and Technology, 2011

The structural organization of chitosan hydrogel beads (CSBs) formed by various anionic surfactan... more The structural organization of chitosan hydrogel beads (CSBs) formed by various anionic surfactants, sodium dodecyl sulfate (SDS), sodium decyl sulfate (DS), dodecyl benzenesulfonic acid sodium salt (SDBS), and dioctyl sulfosuccinate sodium salt (DSS), and their applications as adsorbents for environmental purifications were investigated using Congo red (CR) as a model dye. The adsorption capacities of CSB as a function of

Research paper thumbnail of Mechanistic enzymology in non-aqueous media

Pure and Applied Chemistry, 2000

Research paper thumbnail of Effect of coagulant addition on the sedimentation of a surfactant-containing washing solution used for phenanthrene-contaminated soil

Korean Journal of Chemical Engineering, 2011

ABSTRACT The coagulation of soil particles from a soil-washing solution containing the nonionic s... more ABSTRACT The coagulation of soil particles from a soil-washing solution containing the nonionic surfactant Triton X-100 (TX100) was investigated using various coagulants, such as chitosan (CS), polyacrylamide (PAA), and polyaluminum chloride (PAC). Soil contaminated with phenanthrene (PHE) was washed with aqueous TX100 solutions at concentrations ranging from 0.1 to 20 g/L. The effectiveness of CS (5 mg/L) as a coagulant in the system was compared with PAA (50mg/L) and PAC (50 mg/L), and the results indicated that the system with CS exhibited a more effective separation of soil than those with PAA and PAC. The removal efficiency of PHE (R j =81.7%) and the selective separation factor (SSF=14.2) at 10 g/L TX100 were the highest for the system with CS (5 mg/L), indicating that the selection of CS as a coagulant in surfactant-mediated soil washing markedly improved both PHE removal and soil separation. Key wordsChitosan–Coagulation–Phenanthrene–Soil Washing–Surfactant

Research paper thumbnail of Kinetic analysis of the mechanism for subtilisin in essentially anhydrous organic solvents

Enzyme and Microbial Technology, 1993

Research paper thumbnail of Adsorption of a cationic dye, methylene blue, on to chitosan hydrogel beads generated by anionic surfactant gelation

Environmental Technology, 2011

Chitosan hydrogel beads (CSB) formed by sodium dodecyl sulphate (SDS) gelation were used for the ... more Chitosan hydrogel beads (CSB) formed by sodium dodecyl sulphate (SDS) gelation were used for the removal of a cationic dye, methylene blue (MB), from aqueous solutions. The adsorption capacity of chitosan beads (CB) formed by alkali gelation was low because of charge repulsions between the chitosan (CS) and the MB. The adsorption capacity of CSB (4 g/L SDS gelation) for MB (100 mg/L) was 129.44 mg/g, and it decreased significantly with increasing SDS concentration during gelation. This decrease was a result of increased density of the CSB membrane materials. The CSB membrane materials formed with the 4 g/L SDS gelation showed the highest volumetric adsorption capacity. The MB adsorption on to CB and CSB increased with increasing values for the initial pH of solution. Data from both CB and CSB showed good fit to Sips isotherm models, and the maximum adsorption capacity of CSB (226.24 mg/g) was higher than that of CB (99.01 mg/g).

Research paper thumbnail of Effect of chitosan addition on phenanthrene solubilization in anionic or cationic surfactant solutions

Desalination and Water Treatment, 2012

ABSTRACT The solubility of solid phenanthrene (PHE) powder in aqueous solutions of surfactant and... more ABSTRACT The solubility of solid phenanthrene (PHE) powder in aqueous solutions of surfactant and chitosan (CS) was evaluated by varying the composition of aqueous mixtures. Cetyltrimethyl ammoniumbromide (CTAB) and sodium dodecyl sulfate (SDS) were used as model cationic and anionic surfactants, respectively. CS at a particular concentration in the mixture especially above the CMC value of the anionic surfactant exhibited somewhat higher PHE solubility values than surfactant itself. CS (20 mg/l)-SDS (20 g/l) solution showed higher PHE solubility (422.05 mg/l) than that of 20 g/l SDS (377.92 mg/g). However, CS-CTAB did not show any additional enhancing effect on PHE solubilization, and CS (5 mg/l)-CTAB (10 g/l) solution showed almost similar PHE solubility (867.23 mg/l) of 10 g/l CTAB (865.25 mg/g). The maximum increase in absorbance value of a 20 ml CS solution (5, 20 and 100 mg/l) at 540 nm with stepwise addition of SDS (10 g/l) was found at a SDS concentration much less than its CMC value (2.33 g/l) in the mixture, indicating strong complex formation between CS and SDS because of oppositely charged molecules in the experimental conditions

Research paper thumbnail of Coagulation of soil suspensions containing nonionic or anionic surfactants using chitosan, polyacrylamide, and polyaluminium chloride

Chemosphere, 2009

Effective coagulation and separation of particles in a soil-washed solution is required for a suc... more Effective coagulation and separation of particles in a soil-washed solution is required for a successful soil washing process. The effectiveness of chitosan (CS), a polycationic biodegradable polymer, as a coagulant was compared to polyacrylamide (PAA) and polyaluminium chloride (PAC) for the coagulation of a soil suspension (5 gL(-1)). The effect of surfactants in the coagulation process was investigated using Triton X-100 (TX-100), a nonionic surfactant, and sodium dodecyl sulfate (SDS), an anionic surfactant. CS (5 mgL(-1)) removed 86% and 63% of the suspended soil in the presence of TX-100 (5 gL(-1)) and SDS (5 gL(-1)), respectively, after 30 min at a pH of 6. The results prove that coagulation in the presence of TX-100 is more effective than with SDS. CS was found to be more efficient compared to PAA and PAC under all coagulation conditions. The optimum concentration of CS required for maximum coagulation of soil suspension was 5 mgL(-1). PAA and PAC could not achieve the same degree soil removal as CS even after increasing their concentrations up to 50 mgL(-1). Maximum levels of 50% and 60% soil removal were achieved using PAA (50 mgL(-1)) and PAC (50 mgL(-1)), respectively, after 30 min from a 5 gL(-1) suspension containing TX-100 (5 gL(-1)). The soil coagulation process was found to decrease with an increase in the pH of the suspension, and maximum coagulation was achieved with an acidic pH.