Experimental studies in the dead-end ultrafiltration of dextran: analysis of concentration polarization

Zaidi, S.K; Kumar, Ashwani

doi:10.1016/s1383-5866(03)00207-7

Cited by 24 publications

(16 citation statements)

References 20 publications

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“…ME 4.6) for 2 h. Ultrasonic treatment helped to make a suspension without any large aggregates. UF of silica suspension was done in an unstirred batch cell; details of the experimental set-up and method are given elsewhere [21]. Flux values were reproducible within 0.1%.…”

Section: Materials and Apparatusmentioning

confidence: 99%

Experimental analysis of a gel layer in dead-end ultrafiltration of a silica suspension

Zaidi

Kumar

2005

Desalination

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Section: Materials and Apparatusmentioning

confidence: 99%

Experimental analysis of a gel layer in dead-end ultrafiltration of a silica suspension

Zaidi

Kumar

2005

Desalination

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“…However, the effects of solvent on CP and gel formation have not been studied. This work is the extension of our previous studies and reports the effects of ethanol-water blends on flux, gel formation and polarization time [10,11]. The effect of initial solute concentration to form a gel in ultrafiltration of PEG was also studied.…”

Section: Introductionmentioning

confidence: 71%

“…In our previous study [11] it was shown that dextran T40 at feed concentration of 5 kg/m 3 forms CP layer and does not form gel. In order to verify the effects of ethanol concentration on CP layer, we blended ethanol at various concentrations in dextran-water solution.…”

Section: Resultsmentioning

confidence: 93%

“…All experiments were performed with a commercial ultrafiltration stirred cell unit (Amicon, USA). A detailed description of experimental set-up is given elsewhere, Zaidi and Kumar [11]. Initially, pure water permeation (PWP) was measured for new membrane followed by solvents that were blends of ethanol and water.…”

Section: Apparatusmentioning

confidence: 99%

“…We have reported [10,11] gel formation with PEG and analysis of concentration polarization with dextran along with a procedure for differentiating between concentration polarization and gel formation with pure water. However, the effects of solvent on CP and gel formation have not been studied.…”

Section: Introductionmentioning

confidence: 99%

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Effects of ethanol concentration on flux and gel formation in dead end ultrafiltration of PEG and dextran*1

Zaidi

Kumar

2004

Journal of Membrane Science

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The phenomenon of concentration polarization and gel formation plays an important role in ultrafiltration of macromolecules from water. However, there is lack of studies on similar phenomena for macromolecule ultrafiltration from blends of aqueous and non-aqueous solvents. This paper reports the effect of ethanol concentration on flux in ultrafiltration of polyethylene glycol and dextran with a solvent resistant polymeric membrane. Transient filtration data, collected after steady state, was utilized to determine actual filtration resistance and contribution of polarization using the osmotic pressure model. It was observed that both steady state flux and gel formation were significantly influenced in the ultrafiltration of both PEG and dextran from blended solvents. It was also observed that the onset of gel formation for PEG and concentration polarization for dextran in blended solvents occurred at significantly higher bulk solute concentrations than in water alone.

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Application of a dense gas technique for sterilizing soft biomaterials

Karajanagi

Yoganathan

Mammucari

et al. 2011

Biotech & Bioengineering

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Sterilization of soft biomaterials such as hydrogels is challenging because existing methods such as gamma irradiation, steam sterilization, or ethylene oxide sterilization, while effective at achieving high sterility assurance levels (SAL), may compromise their physicochemical properties and biocompatibility. New methods that effectively sterilize soft biomaterials without compromising their properties are therefore required. In this report, a dense-carbon dioxide (CO2)-based technique was used to sterilize soft polyethylene glycol (PEG)-based hydrogels while retaining their structure and physicochemical properties. Conventional sterilization methods such as gamma irradiation and steam sterilization severely compromised the structure of the hydrogels. PEG hydrogels with high water content and low elastic shear modulus (a measure of stiffness) were deliberately inoculated with bacteria and spores and then subjected to dense CO2. The dense CO2-based methods effectively sterilized the hydrogels achieving a SAL of 10−7 without compromising the viscoelastic properties, pH, water-content, and structure of the gels. Furthermore, dense CO2-treated gels were biocompatible and non-toxic when implanted subcutaneously in ferrets. The application of novel dense CO2-based methods to sterilize soft biomaterials has implications in developing safe sterilization methods for soft biomedical implants such as dermal fillers and viscosupplements.

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Experimental studies in the dead-end ultrafiltration of dextran: analysis of concentration polarization

Cited by 24 publications

References 20 publications

Experimental analysis of a gel layer in dead-end ultrafiltration of a silica suspension

Experimental analysis of a gel layer in dead-end ultrafiltration of a silica suspension

Effects of ethanol concentration on flux and gel formation in dead end ultrafiltration of PEG and dextran*1

Application of a dense gas technique for sterilizing soft biomaterials

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