Ion Exchange Dialysis Research Articles

Molecular purification, and kinetic study of the enzyme glutathione peroxidase in patients with cardiovascular disease

This study was conducted to evaluate serum glutathione peroxidase activity and partial purification of the enzyme from the serum of heart attack patients using a precipitant or what is called salting out, ion exchange dialysis using DEAE-Cellulose, and gel filtration using Sephadex G100 gel. This study was conducted on 90 samples, (60) patients whose ages ranged between (35-75) years and control (30) individuals whose ages ranged between (23-55). It showed that the number of purification times was (4.64), and the enzyme yield was (40%). The specific activity was (1.3 U/mg). Likewise, kinetic studies were carried out in which values of Km and Vmax of glutathione peroxidase were (16.66 mM) of Vmax, and (0.909 IU/L) of Km, and the optimal concentration of the base material was (100 mmol/L). The optimal temperature for enzyme action was (37°C), while the optimal pH was (7.2), and the molecular weight of glutathione peroxidase was (23 kDa). The study also studied the effect of carvedilol as an inhibitor of the enzyme glutathione peroxidase, and the results showed a decrease in enzyme activity, and the type of inhibition was uncompetitive.

Ion Exchange Dialysis for Aluminium Transport through a Face-Centred Central Composite Design Approach

An ion exchange dialysis (IED) is used in the recovery of aluminium from residue. In this paper, the face-centred central composite design (FC-CCD) of the response surface methodology (RSM) and desirability approach is used for experimental design, modelling and process optimization of a counter flow IED system. The feed concentration, feed flowrate, sweep flowrate and sweep concentration were selected as the process variables, with the Al transport across a Nafion 117 membrane as the target response. A total of 30 experimental runs were conducted with six centre points. The response obtained was analysed by analysis of variance (ANOVA) and fitted to a second-order polynomial model using multiple regression analysis. The actual R2 and standard deviation of the model are 0.9548 and 0.2932, respectively. Depending on the time zone of reference (24 h or 32 h), the highest enrichment of >1.50 was achieved. The designed variables were numerically optimized by applying the desirability function to achieve the maximum Al transport. The optimised condition values were found to be a feed concentration of 1600 ppm, feed flowrate of 61.76%, sweep flowrate of 37.50% and sweep concentration of 0.75 N for the 80% target response at 32 h. Overall, the model can be used to effectively predict Al recovery using the designed system.

Effect of ion exchange dialysis process variables on aluminium permeation using response surface methodology

This study investigated aluminum permeation using a counter flow ion exchange dialysis (IED) system. The optimum conditions for permeation were investigated using response surface methodology (RSM). Effect of four factors- feed concentration (100-2,000 ppm, A), feed flow rate (25-85%, B), sweep concentration (0.25-1 N HCl, C) and sweep flow rate (25-85%, D) were studied using face centered central composite (FC-CCD) statistical experimental design. A RSM model was developed based on the experimental permeation data and the response plot was developed. The FC-CCD model predicted permeation correlated with the experimental data. The regression coefficient (R<sup>2</sup>) was found to be 0.9568. The experiment showed the ascending order of the effect of the variables is D < B < C < A. In a counter flow IED for Al permeation, the sweep flow rate is insignificant (p > 0.05). Experimental validation demonstrated for target permeation of 70% was 68.8% ± 2.22%. This suggested that the RSM was a suitable tool in optimizing Al-permeation.

Batch ion-exchange dialysis to extract nitrate from drinking water: a simplified ion transport model for the best membrane selection

The performances of four commercial anion-exchange membranes in the extraction of nitrate ions from water were compared in dialysis against a concentrated sodium chloride solution. The characteristic time derived from a simplified transport model for ion dialysis appears to be a convenient quantitative criterion for a selection of the best membrane for the removal of an undesirable ion. For the nitrate removal from sulfate-containing water to make it drinkable, the Neosepta ACS anion-exchange membrane appears to be the best choice due to the fast and selective removal of nitrate obtained.

Elimination of ion-exchanged precursors to poly(phenylenevinylene)

Poly(xylylidenetetrahydrothiophenium) (PXT) precursors to poly(phenylenevinylene) (PPV) containing F - , Cl - , Br - and acetate counterions were prepared by ion exchange dialysis of the chloride polyelectrolyte. TGA of cast films of PXT indicates that elimination of PXT acetate to PPV occurs at much higher temperature than the halides. The identity of the anion has a marked effect on the limiting electronic conductivity of sulfuric acid doped PPV. Studies on solution elimination kinetics reveal ion association of acetate with aqueous PXT.