Fundamentals of Particle Fouling in Membrane Processes

Bhattacharjee Subir,Hong Seungkwan The Membrane Society of Korea 2005 Korean Membrane Journal Vol.7 No.1

The permeate flux decline due to membrane fouling can be addressed using a variety of theoretical stand-points. Judicious selection of an appropriate theory is a key toward successful prediction of the permeate flux. The essential criterion f3r such a decision appears to be a detailed characterization of the feed solution and membrane properties. Modem theories are capable of accurately predicting several properties of colloidal systems that are important in membrane separation processes from fundamental information pertaining to the particle size, charge, and solution ionic strength. Based on such information, it is relatively straight-forward to determine the properties of the concentrated colloidal dispersion in a polarized layer or the cake layer properties. Incorporation of such information in the framework of the standard theories of membrane filtration, namely, the convective diffusion equation coupled with an appropriate permeate transport model, can lead to reasonably accurate prediction of the permeate flux due to colloidal fouling. The schematic of the essential approach has been delineated in Figure 5. The modern approaches based on appropriate cell models appear to predict the permeate flux behavior in crossflow membrane filtration processes quite accurately without invoking novel theoretical descriptions of particle back transport mechanisms or depending on adjust-able parameters. Such agreements have been observed for a wide range of particle size ranging from small proteins like BSA (diameter ${\~}$6 nm) to latex suspensions (diameter ${\~}1\;{\mu}m$). There we, however, several areas that need further exploration. Some of these include: 1) A clear mechanistic description of the cake formation mechanisms that clearly identifies the disorder to order transition point in different colloidal systems. 2) Determining the structure of a cake layer based on the interparticle and hydrodynamic interactions instead of assuming a fixed geometrical structure on the basis of cell models. 3) Performing well controlled experiments where the cake deposition mechanism can be observed for small colloidal particles (< $1\;{\mu}m$). 4) A clear mechanistic description of the critical operating conditions (for instance, critical pressure) which can minimize the propensity of colloidal membrane fluting. 5) Developing theoretical approaches to account for polydisperse systems that can render the models capable of handing realistic feed solutions typically encountered in diverse applications of membrane filtration.

Potential of inherent RGD containing silk fibroin-poly (Є-caprolactone) nanofibrous matrix for bone tissue engineering

Bhattacharjee, Promita,Kundu, Banani,Naskar, Deboki,Kim, Hae-Won,Bhattacharya, Debasis,Maiti, T. K.,Kundu, S. C. Springer 2016 Cell and tissue research Vol. No.

<P>The current study deals with the fabrication and characterization of blended nanofibrous scaffolds of tropical tasar silk fibroin of Antheraea mylitta and poly (D'-caprolactone) to act as an ideal scaffold for bone regeneration. The use of poly (D'-caprolactone) in osteogenesis is well-recognized. At the same time, the osteoconductive nature of the non-mulberry tasar fibroin is also established due to its internal integrin binding peptide RGD (Arg-Gly-Asp) sequences, which enhance cellular interaction and proliferation. Considering that the materials have the required and favorable properties, the blends are formed using an equal volume ratio of fibroin (2 and 4 wt%) and poly (D'-caprolactone) solution (10 wt%) to fabricate nanofibers. The nanofibers possess an average diameter of 152 +/- 18 nm (2 % fibroin/PCL) and 175 +/- 15 nm (4 % fibroin/PCL). The results of Fourier transform infrared spectroscopy substantiates the preservation of the secondary structure of the fibroin in the blends indicating the structural stability of the neo-matrix. With an increase in the fibroin percentage, the hydrophobicity and thermal stability of the matrices as measured from melting temperature T-m (using DSC) decrease, while the mechanical strength is improved. The blended nanofibrous scaffolds are biodegradable, and support the viability and proliferation of human osteoblast-like cells as observed through scanning electron and confocal microscopes. Alkaline phosphatase assay indicates the cell proliferation and the generation of the neo-bone matrix. Taken together, these findings illustrate that the silk-poly (D'-caprolactone) blended nanofibrous scaffolds have an excellent prospect as scaffolding material in bone tissue engineering.</P>

Low algal diversity systems are a promising method for biodiesel production in wastewater fed open reactors

Bhattacharjee, Meenakshi,Siemann, Evan The Korean Society of Phycology 2015 ALGAE Vol.30 No.1

Planktivorous fish which limit zooplankton grazing have been predicted to increase algal biodiesel production in wastewater fed open reactors. In addition, tanks with higher algal diversity have been predicted to be more stable, more productive, and to more fully remove nutrients from wastewater. To test these predictions, we conducted a 14-week experiment in Houston, TX using twelve 2,270-L open tanks continuously supplied with wastewater. Tanks received algal composition (monocultures or diverse assemblage) and trophic (fish or no fish) treatments in a full-factorial design. Monocultures produced more algal and fatty acid methyl ester (FAME) mass than diverse tanks. More than 80% of lipids were converted to FAME indicating potentially high production for conversion to biodiesel (up to $0.9T\;ha^{-1}y^{-1}$). Prolific algal growth lowered temperature and levels of total dissolved solids in the tanks and increased pH and dissolved oxygen compared to supply water. Algae in the tanks removed 91% of nitrate-N and 53% of phosphorus from wastewater. Monocultures were not invaded by other algal species. Fish did not affect any variables. Our results indicated that algae can be grown in open tank bioreactors using wastewater as a nutrient source. The stable productivity of monocultures suggests that this may be a viable production method to procure algal biomass for biodiesel production.

Effect of graphite particulate on mechanical properties of glass fibre reinforced composite

Bhattacharjee, Antara,Roy, Kanchan,Nanda, B.K. The Society for Aerospace System Engineering 2020 International Journal of Aerospace System Engineer Vol.7 No.1

The recent trend is increasing towards the usage of polymer matrix composites since they have a wide variety of applications. They have applications in the field of aircraft and space industry, sporting goods, medical devices, marine and automotive applications and also in commercial usage. The most commonly used fibre-reinforced polymer matrix composite is Glass fibre reinforced epoxy (GFRE) composite which is used in aviation, sports and automotive industries. However, the strength of GFRE composites is not adequate for structural applications. Therefore, the current research focuses on increasing the strength of GFRE composites by reinforcing with micro Graphite (Gr) particulates. The Gr used is an ultra-fine powder with particle size 250 ㎛. Gr is known to have good wear resistance, thermal conductivity and can operate at high temperatures. Gr particulates are mixed with the epoxy matrix in various weight ratios. Hand-lay technique is used for fabricating the composites. Mechanical properties such as tensile strength, elongation, compressive strength and flexural strength are obtained experimentally to study the effect of change in Gr content (0-5 wt. %). The tests were done as per ASTM standards.

Kinetics of Oxidation of Nitrotoluenes by Acidic Hexacyanoferrate (Ⅲ)

Bhattacharjee, A. K.,Mahanti, M. K. Korean Chemical Society 1983 Bulletin of the Korean Chemical Society Vol.4 No.3

The reaction of hexacyanoferrate (Ⅲ) with nitrotoluenes in aqueous acetic acid containing perchloric acid(1.0 M) at $50^{\circ}C$ gave the corresponding aldehyde as the major product. The order with respect to each of the reactants ― substrate, oxidant and acid ― was found to be unity. The Hammett plot yielded a ${\sigma}^+$ value of -1.30, and the kinetic isotope effect gave a $k_H/k_D$ value of 6.2. The pathway for the conversion of the nitrotoluenes to the products has been mechanistically visualized as proceeding through the benzylic radical intermediate, formed in the rate determining step of the reaction.

Solvothermal synthesis of Fe-MOF-74 and its catalytic properties in phenol hydroxylation.

Bhattacharjee, Samiran,Choi, Jung-Sik,Yang, Seung-Tae,Choi, Sang Beom,Kim, Jaheon,Ahn, Wha-Seung American Scientific Publishers 2010 Journal of nanoscience and nanotechnology Vol.10 No.1

<P>A Fe-containing metal-organic framework, Fe-MOF-74, was solvothermally synthesized using FeCl2.4H2O and 2,5-di-hydroxy-1,4-benzenedicarboxylic acid. Characterization was conducted by XRD, BET surface area measurement, FT-IR spectroscopy, TGA, and elemental analysis, which confirmed successful preparation of Fe-MOF-74 having an identical framework structure to that reported for MOF-74. Fe-MOF-74 was found to be an effective heterogeneous catalyst for the hydroxylation of phenol using H2O2 as an oxidant; 60% phenol conversion was achieved at 20 degrees C in water with 68 and 32% selectivity to catechol and hydroquinone, respectively. The effect of temperature, phenol/H2O2 mole ratio, catalyst quantity, and solvent on catalytic performance was discussed, and a reaction mechanism is proposed based upon the experimental results.</P>

Pd Nanoparticles Supported on MIL-101: An Efficient Recyclable Catalyst in Oxidation and Hydrogenation Reactions

Bhattacharjee, S.,Kim, J.,Ahn, W.-S. American Scientific Publishers 2014 Journal of nanoscience and nanotechnology Vol.14 No.3

Pd nanoparticles supported on the chromium terephthalate metal organic framework MIL-101 (Pd/MIL-101) in different loadings (0.9 and 4.5 wt%) have been successfully prepared through a simple Pd-acetate adsorption and reduction in acetone, and tested as catalyst for selected liquid phase oxidation and hydrogenation reactions. The materials were characterized by XRD, N-2 adsorption-desorption isotherm, TEM, SEM-EDX and ICP analysis. The parent MIL-101 structure was found well preserved after formation of Pd nanoparticles and after catalytic reaction runs. The present catalyst afforded good activity and selectivity for the oxidation of benzyl alcohol to benzaldehyde with 85% conversion and 97% selectivity using air (1 atm) at 85 degrees C after 14 h. The catalyst also showed good activity in the hydrogenation of the C=C bond in alkenes to corresponding alkanes and also benzaldehyde to benzyl alcohol at room temperature using H-2 (1 atm). Rigorous test results confirmed that Pd-nanoparticles supported on MIL-101 are responsible for the catalytic reactions occurred. Pd/MIL-101 was reusable several times without losing the structural integrity and initial activity, and demonstrated significantly higher catalytic activities than those by a commercial Pd catalyst supported on activated carbon.

Comparative Reverse Screening Approach to Identify Potential Anti-neoplastic Targets of Saffron Functional Components and Binding Mode

Bhattacharjee, Biplab,Vijayasarathy, Sandhya,Karunakar, Prashantha,Chatterjee, Jhinuk Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.11

Background: In the last two decades, pioneering research on anti-tumour activity of saffron has shed light on the role of crocetin, picrocrocin and safranal, as broad spectrum anti-neoplastic agents. However, the exact mechanisms have yet to be elucidated. Identification and characterization of the targets of bioactive constituents will play an imperative role in demystifying the complex anti-neoplastic machinery. Methods: In the quest of potential target identification, a dual virtual screening approach utilizing two inverse screening systems, one predicated on idTarget and the other on PharmMapper was here employed. A set of target proteins associated with multiple forms of cancer and ranked by Fit Score and Binding energy were obtained from the two independent inverse screening platforms. The validity of the results was checked by meticulously analyzing the post-docking binding pose of the picrocrocin with Hsp90 alpha in AutoDock. Results: The docking pose reveals that electrostatic and hydrogen bonds play the key role in inter-molecular interactions in ligand binding. Picrocrocin binds to the Hsp90 alpha with a definite orientation appropriate for nucleophilic attacks by several electrical residues inside the Hsp90-alpha ATPase catalytic site. Conclusion: This study reveals functional information about the anti-tumor mechanism of saffron bioactive constituents. Also, a tractable set of anti-neoplastic targets for saffron has been generated in this study which can be further authenticated by in vivo and in vitro experiments.

High strength and formable Mg-6.2Zn-0.5Zr-0.2Ca alloy sheet processed by twin roll casting

Bhattacharjee, T.,Suh, B.C.,Sasaki, T.T.,Ohkubo, T.,Kim, N.J.,Hono, K. Elsevier Sequoia 2014 Materials science & engineering. properties, micro Vol.609 No.-

Twin roll cast and hot rolled Mg-6.2wt%Zn alloys microalloyed with Zr, Ca, and Ag show tensile yield strength exceeding 300MPa in the T6 (peak-aged) condition with reasonable formability in the T4 condition. The addition of Zr and Ca plays a critical role in the development of weak textured recrystallized microstructure in Mg-6.2wt%Zn alloys so Mg-6.2Zn-0.5Zr-0.2Ca (wt%) alloy shows equivalent mechanical properties with Mg-6.2Zn-0.5Zr-0.2Ca-0.4Ag (wt%) alloy even without expensive Ag.

Purification of a Trypsin Inhibitor from Cocculus hirsutus and Identification of Its Biological Activity

Bhattacharjee, Chumki,Manjunath, Nagenahalli Huchappa,Prasad, Doddananjappa Theertha 한국작물학회 2009 Journal of crop science and biotechnology Vol.12 No.4

Proteinase inhibitors play a significant role in plant defense against insect pests and phytopathogens by inhibiting their proteases. A thermotolerant monomeric trypsin inhibitor with molecular weight ~18kD was purified from Cocculus hirsutus (ChTI) using trypsin sepharose affinity column. Western blot analysis using ChTI IgY revealed its presence in vegetative parts and seeds. The second and third instar larvae of H.armigera fed with ChTI (5000TIU/ml) resulted in 84.59 and 58.71% reduction in mean larval weight respectively. An increase in the larval growth period was observed in ChTI fed larvae at all instars and inhibitor fed larvae could not complete their life cycle. ChTI caused 74 and 59.53% inhibition of bovine trypsin and Helicoverpa gut proteases respectively. ChTI exhibited strain specificity and inhibited growth and development of plant fungal pathogens. Bioassay studies on yeast strains indicated that ${\Delta}YNK$ and MNN1 are more sensitive to ChTI. The results suggest that phosphodiester linkage in cell wall components is likely to be the key determinants for binding of ChTI. Taken together, these studies indicate that ChTI is a potential candidate for development of transgenic plants against foliar diseases and insect pests.