PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “ION EXCHANGE RESINS”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 109 records · Page 6Linked to original sources
PubMed1975

Determination of the inner surface of macroporous ion exchange resins.

Study on macroporours IX resins and the pore structure. In addition to ion exchange reactions, macroporous ion exchange resins also show adsorptive properties which are due to the large pores of the resin beads and to the inner surface inside the beads. To measure this surface and the pore radii requires very precise fixation of the condition existing prior to the drying of the water-moist resin beads. Such stabilizing fixation can be achieved by displacing the regain water by isopropyl alcohol and subsequent drying for measuring the pore data.

Ion Exchange Resins↗
PubMed1979

Chromatography of xanthines on ion-exchange resins.

Short columns of a 4% crosslinked cation-exchange resin gave good chromatography of xanthines, including caffeine, theophylline and hypoxanthine, and related polar aromatic compounds. Elution volumes and sequences can be modified by changing pH, solvent composition and resin counter-ion. A macroporous cation-exchange resin showed exaggerated counter-ion effects. A method is described for determining caffeine and theophylline in blood serum, using the 4% crosslinked resin with aqueous sodium phosphate eluent of pH 7.5; the temperature was 65 degrees. Detection limits are 10 ng and less.

Caffeine↗
PubMed1988

Rate of release of organic carboxylic acids from ion-exchange resins.

Organic anions with similar properties, but different molecular weights, were bound to anion-exchange resins with different cross-linking. It was found that the capacity of the ion-exchange resin for the anions, the percentage of organic anion released, and the rate of release depends on the crosslinking of the ion-exchange resin, the molecular weight of the anion, and the moisture content of the resin. Self-diffusion coefficients for the release rates were determined.

Anion Exchange Resins↗
PubMed2002

Oxidative pyrolysis of organic ion exchange resins in the presence of metal oxide catalysts.

Pretreatment of the organic ion exchange resins by oxidative pyrolysis is effective for volume reduction before vitrification. In this work, pyrolysis of two nuclear-grade resins, Purolite NRW100 (cationic) and NRW400 (anionic), was examined using a laboratory-scale theromgravimetric analyzer (TGA) in air. It was shown that the cationic resin was harder to degrade and was less volatile compared to anionic resin. Off-gas data revealed the presence of SO2, CO2, CO, and H2O during oxidative pyrolysis of cationic resin from 30 to 800 degrees C. Trimethylamine, CO2, CO, and ethyl formate were found in the case of anionic resin. In addition, oxidative pyrolysis of the mixed resins (50/50 wt.%) showed the existence of the gases nearly at the temperatures where the gases would evolve if the results of two different resins were superimposed. Several metal salts including CuSO4*5H2O, CuO, and FeSO4*7H2O, as well as the ions Cu2+ pre-loaded on the resins had a catalytic effect on the oxidative pyrolysis of cationic resins, in which the decomposition of functional groups and polymer matrices was enhanced. Such catalytic effect was highlighted by a large decrease in activation energy calculated according to a degradation mechanism involving four consecutive reactions.

Catalysis↗
PubMed2002

Effects of competitive ions, humic acid, and pH on removal of ammonium and phosphorous from the synthetic industrial effluent by ion exchange resins.

The removal of the ammonium and phosphorous from the synthetic industrial effluent by the ion exchange resins was studied in this paper, aiming at the determination of the effects of competitive ions, humic acid, pH and resin amount. The kinetic experiments show that the equilibrium time for the removal of both contaminants in the absence and presence of the competing matters was 4 h. Na+ and K+ significantly reduced the ammonium removal percentage, while the existence of Mg2+, Ca2+ and humic acid also had a negative influence. Adsorption of ammonium ions in both absence and presence of Na+ and K+ observed the linear isotherm, however, it did not follow commonly used isotherms in the presence of Na+, K+, Mg2+, Ca2+ and humic acid. The phosphorous removal decreased in the presence of the competitive matters, such as Cl-, CO3(2-), SO4(2-) and humic acid. Higher pH can cause higher phosphorous removal percentage. A decrease in the solution pH was observed in the phosphorous removal experiments, possibly due to the ion exchange and the adsorption of OH-. Uptake of humic acid by the resins was observed. Finally, a series of fixed-bed experiments were performed, showing that the performance was dependent on the empty bed contact time (EBCT). Higher EBCT would cause higher bed volumes of both treated ammonium and phosphorous.

Humic Substances↗
PubMed2006

Factorial experimental design for recovering heavy metals from sludge with ion-exchange resin.

Wastewaters containing heavy metals are usually treated by chemical precipitation method in Taiwan. This method can remove heavy metals form wastewaters efficiently, but the resultant heavy metal sludge is classified as hazardous solid waste and becomes another environmental problem. If we can remove heavy metals from sludge, it becomes non-hazardous waste and the treatment cost can be greatly reduced. This study aims at using ion-exchange resin to remove heavy metals such as copper, zinc, cadmium, and chromium from sludge generated by a PCB manufacturing plant. Factorial experimental design methodology was used to study the heavy metal removal efficiency. The total metal concentrations in the sludge, resin, and solution phases were measured respectively after 30 min reaction with varying leaching agents (citric acid and nitric acid); ion-exchange resins (Amberlite IRC-718 and IR-120), and temperatures (50 and 70 degrees C). The experimental results and statistical analysis show that a stronger leaching acid and a higher temperature both favor lower heavy metal residues in the sludge. Two-factors and even three-factor interaction effects on the heavy metal sorption in the resin phase are not negligible. The ion-exchange resin plays an important role in the sludge extraction or metal recovery. Empirical regression models were also obtained and used to predict the heavy metal profiles with satisfactory results.

Analysis of Variance↗