Silver anion exchange resins

Anion exchange resin. Proceed as in the previous experiment using 1.0 g, accurately weighed, of the air-dried strongly basic anion exchanger (e.g. Duolite A113, chloride form). Fill the 250 mL separatory funnel with ca 0.25M sodium nitrate solution, and allow this solution to drop into the column at the rate of about 2 mL per minute. Collect the effluent in a 500 mL conical flask, and titrate with standard 0.1M silver nitrate using potassium chromate as indicator. 

Theory. The anion exchange resin, originally in the chloride form, is converted into the nitrate form by washing with sodium nitrate solution. A concentrated solution of the chloride and bromide mixture is introduced at the top of the column. The halide ions exchange rapidly with the nitrate ions in the resin, forming a band at the top of the column. Chloride ion is more rapidly eluted from this band than bromide ion by sodium nitrate solution, so that a separation is possible. The progress of elution of the halides is followed by titrating fractions of the effluents with standard silver nitrate solution. 

Silver Silver pre-concentrated on Deacidite FF IP anion exchange resin, eluted with thiourea Neutron activation analysis < 40 ng/1 [559]... 

Elemental composition P 38.73%, H 1.26%, O 60.01%. The compound may be identified by physical properties alone. It may be distinguished from ortho and pyrophosphates by its reaction with a neutral silver nitrate solution. Metaphosphate forms a white crystalline precipitate with AgNOs, while P04 produces a yellow precipitate and P20 yields a white gelatinous precipitate. Alternatively, metaphosphate solution acidified with acetic acid forms a white precipitate when treated with a solution of albumen. The other two phosphate ions do not respond to this test. A cold dilute aqueous solution may be analyzed for HPO3 by ion chromatography using a styrene divinylbenzene-based low-capacity anion-exchange resin. 

Pyridine (1.0 gm) added as a polymerization inhibitor. b S(CH2CH2OH)2 (6.0 gm) added as a catalyst. c Activated carbon with silver oxide or Ni-W sulfide catalyst added. a Anion-exchange resin (40-100 gm) added see U.S. Pat. 2,614,099 (1952). Absolute ethanol (62 gm) and 1 gm of FeCl3 or TiCl3 added. 

The silver chloride electrode gave poor response to iodide and bromide, and so did the silver bromide electrode to iodide. Although the silver iodide electrode responded to all three halides, the peaks are not sufficiently resolved and they are asymmetric. Further, there was a drift of the base line after detection of a halide ion which was not a component of the electrode and this drift caused disturbance in the following peak. This difficulty is eliminated by using hydrous zirconium oxide instead of the anion exchange resin for the chromatography since it reverses the elution order for halide ions. The silver bromide electrode is then the most suitable as the detector for both bromide. 

Reduction of Silver. A 100-mL sample of a silver salt solution containing 5000 ppm of silver at a pH of 4.5 was stirred with 1 g of boro-hydride-form A-26 anion-exchange resin in a beaker for 30 min. The reduced silver powder and the resin were filtered from the solutions. An analysis of the filtrate showed 0.05 ppm silver. The above reduction was also carried out efficiently over a pH range of 4.5-8.5. 

Application of Polymer-Bound Reducing Agents for Silver Recovery from Photographic Fixer. Several 10-mL aliquots of a spent photographic fixer solution containing 0.55% silver were diluted to 100 mL and adjusted to 5 different pH levels 4.5, 5.5, 6.5, 7.5, and 8.5. One gram of borohydride-form A-26 anion-exchange resin was added to each sample. The samples were stirred and allowed to stand at 20 °C for 30 min. 

A 25-mL solution containing 500 ppb of arsenic (Ag3+) was stirred with 1 g of borohydride-form A-26 anion-exchange resin. The reaction vessel was connected to an absorption tube filled with a solution to absorb the volatile hydride of arsenic (i.e., arsine, AsH3). The absorption solution is made by dissolving 1 g of silver diethyldithiocarbamate (SDDC) in 200 mL of pyridine. The volatile arsine is complexed with the SDDC solution to give a colored solution, whose absorbance is... 

The radionuclide with added carrier can be separated from most other long-lived radionuclides by precipitating silver or palladium iodide from dilute niuic acid solution. As indicated in Section 6.3.1, the oxidation state of radioiodine, of which there are several, must be well defined before a separation step can be trusted. Other purification techniques are solvent extraction of iodine oxidized to h into carbon tetrachloride followed by back extraction of the reduced iodide form into water, or sorption of 1 on anion-exchange resin followed by elution with a strong chloride solution (Kleinberg and Cowan 1960). These processes also lend themselves to concentrating the radionuclide from larger solution volumes to attain a lower detection limit. 

Quaternary ammonium hydroxides (4,267-268). The use of an anion-exchange resin for conversion of quaternary ammonium halides into the hydroxide has been published. The method is suitable for even very sensitive compounds and is superior to silver oxide (expensive) or thallous ethoxide (expensive and toxic). 

Scheme 2.4. Schematic representation of the synthesis of silver nanoparticles on anion exchange resin.

The properties of anion-exchange resins of several types have been described in detail by Kraus and Nelson 351-356) and others (557, 358). Selenium(IV), tellurium(IV), and arsenic(III) and (V) can be extracted from a variety of media 359-361). Thallium(III) and antimony(V) can be separated using the iodide and chloride forms of Dowex-1 (5(52, 363). Beryllium(II) was efficiently extracted by the carbonate form 364, 365) and chromium(III) and lead(II) by the phosphate form of AV-17 resin 366). Zinc(II) can be removed from a solution containing several metals (5(57, 368) and silver in concentrations at the 0.04-ppb level can be extracted from seawater (5(59). Cobalt(II), zinc(II), antimony(III), silver(I), and iron(III) ions have also been extracted from spiked seawater samples by anion exchange even though the actual form of the ions in the aged solution was uncertain (570). Anion resins have been modified with Trilon B (577) and with a-hydroxyisobutyronitrile (572) to increase the extraction of several trace-metal pollutants. Amberlite IRA 400 treated with the sulfonic acid derivative of dithizone can be used to concentrate heavy metals (575). 

Fission products may contain the iodine isotopes from to Of these, is considered the most significant hazard in drinking water. Three methods are available for the determination of radioactive iodine in water samples precipitation, sorption on an anion-exchange resin, and distillation. The precipitation method is preferred because it is simple and requires the least time. In the precipitation method, iodate carrier is added to the sample and reduced to iodide with sodium sulfite. The iodide is precipitated as silver iodide. The precipitate is dissolved, and purified with zinc powder and sulfuric acid. The iodide is finally precipitated as palladium iodide, Pdli, for counting in a low-background //-counter, or ///y coincidence system. 

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