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Papers by Kamalesh Sirkar

Research paper thumbnail of Characterization of microporous ECTFE membrane after exposure to different liquid media and radiation

Journal of Membrane Science, 2017

Research paper thumbnail of A composite hollow ®ber membrane-based pervaporation process for separation of VOCs from aqueous surfactant solutions

The separation and recovery of VOCs from surfactant-containing aqueous solutions by a composite h... more The separation and recovery of VOCs from surfactant-containing aqueous solutions by a composite hollow ®ber membranebased pervaporation process has been studied. The process employed hydrophobic microporous polypropylene hollow ®bers having a thin plasma polymerized silicone (PDMS) coating on the outside diameter, trichloroethylene (TCE) as the model contaminant and sodium dodecyl sulfate (SDS) as the surfactant. The feed solution was passed through the ®ber bore; the shell side had vacuum. The process operating parameters, e.g., feed ̄ow rate, TCE and SDS concentrations, were varied over a wide range to investigate their effect on the process performance. Depending on the concentration of the surfactant, separation of VOCs can be achieved via two different conditions, namely, wetted pore and non-wetted pore. The resistances-in-series concept successfully applied earlier to the TCE±water system has been extended to the TCE±SDS±water system for both wetted pore and non-wetted pore co...

Research paper thumbnail of Pilot plant studies of novel membranes and devices for direct contact membrane distillation-based desalination

Journal of Membrane Science, 2008

A small pilot plant for direct contact membrane distillation (DCMD) based desalination was built ... more A small pilot plant for direct contact membrane distillation (DCMD) based desalination was built and operated successfully on a daily basis for 3 months. The operation employed hot brine at 64–93° C and distillate at 20–54° C. The hot brine was either city water, city water ...

Research paper thumbnail of Flow Swing Membrane Absorption−Permeation

Industrial & Engineering Chemistry Research, 1998

A cyclically-operated membrane permeation technique, flow swing membrane permeation (FSMP), has b... more A cyclically-operated membrane permeation technique, flow swing membrane permeation (FSMP), has been studied for effective removal of volatile organic compounds (VOCs) from a gas stream to obtain a highly purified gas stream. Feed gas mixture is supplied to the lumen of hollow fiber membranes for a short period of time; then the feed flow is stopped for a brief period after which the feed gas flow into the fiber lumen is resumed. A vacuum is maintained continuously on the shell side for selective permeation and removal of VOCs from the feed gas mixture. Silicone-coated hollow fibers were employed to bring down the VOC concentration in feed N 2 to as low as 1-5 ppmv from feed concentration levels around 200-300 ppmv. The VOCs investigated were methanol, methylene chloride, acetone, and toluene. The purification capacity of the FSMP process has been shown to be considerably higher than that of the conventional steady-state operation of the membrane. To improve the membrane selectivity drastically, a contained liquid membrane concept was employed also using two sets of silicone-coated hollow fibers and silicone oil on the shell side. The permeate in this flow swing membrane absorptionpermeation (FSMABP) process was almost pure VOC. Results of performances for such novel cyclic processes are presented. The potential of such techniques for various gas separations problems has been pointed out.

Research paper thumbnail of An internally staged hollow-fiber permeator for gas separation

AIChE Journal, 1989

Conventional membrane permeation of gases employ a one-step process between the feed and the prod... more Conventional membrane permeation of gases employ a one-step process between the feed and the product on two sides of a membrane. By applying the overall driving force change through a two-step process using two membranes in one device, we illustrate theoretically the possibility of achieving a much higher enrichment without any extra energy consumption. Such an internally staged permeation is experimentally carried out in a hollow-fiber permeator with two sets of asymmetric cellulose acetate hollow fibers for the systems of 0,-N, (air) and C0,-N ,. The superior enriching performance of the internally staged permeator over the same permeator operated in the conventional mode is demonstrated experimentally. A cocurrent flow pattern is found to be superior to a countercurrent flow pattern for the conditions employed. The simulation model incorporating fiber lumen pressure drop predicts the experimental performance quite well. A further improvement in performance can be achieved by recycling the intermediate pressure shell reject stream to the feed stream. The energy requirement in an internally staged permeator without recycle is less than that of a conventional permeator with permeate recycle.

Research paper thumbnail of Ontophoretic Transdermal Drug Delivery System Using a Conducting Olymeric Membrane

This work investigated th meric membrane as well Model drugs studied were 480.1). The PANi membra... more This work investigated th meric membrane as well Model drugs studied were 480.1). The PANi membra solutions; it provided sat by a simplified mass tran a composite system also were next performed usi anode replaced the Ag an from the PANi|AgCl set we Ag|AgCl set were zero. Fo respectively, 43 ± 15 g/cm 48 ± 20 g/cm2 h and 348 ouse skin queous-organic partitioning the Ag part of Ag|AgCl electrod agent transport rate. Aqueoustested with this novel techniqu such a system did not yield a h

Research paper thumbnail of Separation of solutes from aqueous solutions by contained liquid membranes

AIChE Journal, 1988

The hollow fiber contained liquid membrane (CLM) is a thin liquid film contained in the interstic... more The hollow fiber contained liquid membrane (CLM) is a thin liquid film contained in the interstices of two sets of intermingled microporous hollow fine fibers. Organic CLM-s have been used here for the separation of solutes from an aqueous feed into an aqueous strip. Solutes studied are phenol and acetic acid. The separations are carried out in either hydrophilic or hydrophobic hollow fiber CLM permeator modules, using a variety of organic liquids (e.g., decanol, methyl isobutyl ketone, xylene) as membranes. First-order models have been developed to predict the overall solute transfer coefficients adequately. The transfer coefficient can be enhanced significantly when a chemical reaction is carried out on the strip side using NaOH. The advantages of the CLM structure include operational stability, independent control of membrane phase pressure, automatic replenishment of the lost membrane liquid, and absence of the need for preequilibration. These features are demonstrated here, even for systems with considerable aqueous-organic mutual solubilities.

Research paper thumbnail of Characterization of microporous ECTFE membrane after exposure to different liquid media and radiation

Journal of Membrane Science, 2017

Research paper thumbnail of A composite hollow ®ber membrane-based pervaporation process for separation of VOCs from aqueous surfactant solutions

The separation and recovery of VOCs from surfactant-containing aqueous solutions by a composite h... more The separation and recovery of VOCs from surfactant-containing aqueous solutions by a composite hollow ®ber membranebased pervaporation process has been studied. The process employed hydrophobic microporous polypropylene hollow ®bers having a thin plasma polymerized silicone (PDMS) coating on the outside diameter, trichloroethylene (TCE) as the model contaminant and sodium dodecyl sulfate (SDS) as the surfactant. The feed solution was passed through the ®ber bore; the shell side had vacuum. The process operating parameters, e.g., feed ̄ow rate, TCE and SDS concentrations, were varied over a wide range to investigate their effect on the process performance. Depending on the concentration of the surfactant, separation of VOCs can be achieved via two different conditions, namely, wetted pore and non-wetted pore. The resistances-in-series concept successfully applied earlier to the TCE±water system has been extended to the TCE±SDS±water system for both wetted pore and non-wetted pore co...

Research paper thumbnail of Pilot plant studies of novel membranes and devices for direct contact membrane distillation-based desalination

Journal of Membrane Science, 2008

A small pilot plant for direct contact membrane distillation (DCMD) based desalination was built ... more A small pilot plant for direct contact membrane distillation (DCMD) based desalination was built and operated successfully on a daily basis for 3 months. The operation employed hot brine at 64–93° C and distillate at 20–54° C. The hot brine was either city water, city water ...

Research paper thumbnail of Flow Swing Membrane Absorption−Permeation

Industrial & Engineering Chemistry Research, 1998

A cyclically-operated membrane permeation technique, flow swing membrane permeation (FSMP), has b... more A cyclically-operated membrane permeation technique, flow swing membrane permeation (FSMP), has been studied for effective removal of volatile organic compounds (VOCs) from a gas stream to obtain a highly purified gas stream. Feed gas mixture is supplied to the lumen of hollow fiber membranes for a short period of time; then the feed flow is stopped for a brief period after which the feed gas flow into the fiber lumen is resumed. A vacuum is maintained continuously on the shell side for selective permeation and removal of VOCs from the feed gas mixture. Silicone-coated hollow fibers were employed to bring down the VOC concentration in feed N 2 to as low as 1-5 ppmv from feed concentration levels around 200-300 ppmv. The VOCs investigated were methanol, methylene chloride, acetone, and toluene. The purification capacity of the FSMP process has been shown to be considerably higher than that of the conventional steady-state operation of the membrane. To improve the membrane selectivity drastically, a contained liquid membrane concept was employed also using two sets of silicone-coated hollow fibers and silicone oil on the shell side. The permeate in this flow swing membrane absorptionpermeation (FSMABP) process was almost pure VOC. Results of performances for such novel cyclic processes are presented. The potential of such techniques for various gas separations problems has been pointed out.

Research paper thumbnail of An internally staged hollow-fiber permeator for gas separation

AIChE Journal, 1989

Conventional membrane permeation of gases employ a one-step process between the feed and the prod... more Conventional membrane permeation of gases employ a one-step process between the feed and the product on two sides of a membrane. By applying the overall driving force change through a two-step process using two membranes in one device, we illustrate theoretically the possibility of achieving a much higher enrichment without any extra energy consumption. Such an internally staged permeation is experimentally carried out in a hollow-fiber permeator with two sets of asymmetric cellulose acetate hollow fibers for the systems of 0,-N, (air) and C0,-N ,. The superior enriching performance of the internally staged permeator over the same permeator operated in the conventional mode is demonstrated experimentally. A cocurrent flow pattern is found to be superior to a countercurrent flow pattern for the conditions employed. The simulation model incorporating fiber lumen pressure drop predicts the experimental performance quite well. A further improvement in performance can be achieved by recycling the intermediate pressure shell reject stream to the feed stream. The energy requirement in an internally staged permeator without recycle is less than that of a conventional permeator with permeate recycle.

Research paper thumbnail of Ontophoretic Transdermal Drug Delivery System Using a Conducting Olymeric Membrane

This work investigated th meric membrane as well Model drugs studied were 480.1). The PANi membra... more This work investigated th meric membrane as well Model drugs studied were 480.1). The PANi membra solutions; it provided sat by a simplified mass tran a composite system also were next performed usi anode replaced the Ag an from the PANi|AgCl set we Ag|AgCl set were zero. Fo respectively, 43 ± 15 g/cm 48 ± 20 g/cm2 h and 348 ouse skin queous-organic partitioning the Ag part of Ag|AgCl electrod agent transport rate. Aqueoustested with this novel techniqu such a system did not yield a h

Research paper thumbnail of Separation of solutes from aqueous solutions by contained liquid membranes

AIChE Journal, 1988

The hollow fiber contained liquid membrane (CLM) is a thin liquid film contained in the interstic... more The hollow fiber contained liquid membrane (CLM) is a thin liquid film contained in the interstices of two sets of intermingled microporous hollow fine fibers. Organic CLM-s have been used here for the separation of solutes from an aqueous feed into an aqueous strip. Solutes studied are phenol and acetic acid. The separations are carried out in either hydrophilic or hydrophobic hollow fiber CLM permeator modules, using a variety of organic liquids (e.g., decanol, methyl isobutyl ketone, xylene) as membranes. First-order models have been developed to predict the overall solute transfer coefficients adequately. The transfer coefficient can be enhanced significantly when a chemical reaction is carried out on the strip side using NaOH. The advantages of the CLM structure include operational stability, independent control of membrane phase pressure, automatic replenishment of the lost membrane liquid, and absence of the need for preequilibration. These features are demonstrated here, even for systems with considerable aqueous-organic mutual solubilities.