Exchangers s. Ion exchange

Marcus, Y. Kertes, S. Ion Exchange and Solvent Extraction of Metals, WUey-Interscience, Chichester, 1969. 

Fig. 2.2 Schematic diagram showing the probable steps involved in the hydroxide mechanism. A Diffusion of hydroxide colloidal particles to the substrate, where they adhere (B) and react with S ions (either generated homogeneously in solution or catalyzed by the hydroxide surface). This reaction results in exchange of the hydroxide by sulphide, probably starting at the surface of the colloid and proceeding inward (C). This reaction will occur both at the surface-adsorbed colloids and at those dispersed in the solution. Reaction will continue (as long as the supply of sulphide continues) until most of the hydroxide is converted to sulphide (D) eventually the primary particles of CdS will adhere to each other to form an aggregated film (E) usually the nonadsorbed particles will also aggregate and precipitate out of the solution.

Wahlberg, J. S., and Dewar, R. S., "Ion Exchange on Minerals Comparison of Distribution Coefficients for Strontium Exchange from Solutions Containing One and Two Competing Cations," U. S. Geol. Surv. Bull., (1964), 1140-D. 

J. S. "Ion Exchange Properties of Hydrous Oxides" Proc. 2nd Int. Conf Peaceful Uses Atomic Energy Geneva, 1958 Vol. 28, p. 3,... 

We have previously described ammonia removal with zeolites. However, the development of new methods capable of effective and total ammonia removal from wastewater are extremely attractive in this regard, the ion-exchange removal of ammonia with a Dowex HCR-S ion-exchange resin has been carried out [79],... 

Marcus, Y. and Kertes, A.S., Ion exchange and solvent extraction of metal complexes, Wiley-interscience, London, 1970. 

The relatively high Si/Al content of mordenite confers on it a certain acid stabihty that enables it to be used to remove water from acid gas streams such as reformer recycle hydrogen, reformer catalyst regeneration gas, HCl, CI2, and chlorinated hydrocarbons. It can also be used to treat off-gas for removal of oxides of sulfur and nitrogen (SO and NO ). Mordenite s ion-exchange selectivity for Cs has been used to remove Cs radioisotopes from nuclear waste (Zeolon 900) and it is used in Japan on a plant scale to separate gases from the air. 

While the effect of cation impurities on the surface chemistry of MgO has been investigated in detail, very little is known about anion substitution. Defect formation and excitation energies for S and Se -doped bulk MgO have been calculated [182,183] but there are no data for the surface. In the bulk it has been estimated that the presence of S or Se impurities result in a outward relaxation of the Mg neighbors of 6% and 8%, respectively [182]. A recent report of the 0 "-S exchange reaction on MgO has been reported [184]. The reaction involves adsorption of CS2 on MgO powders and the subsequent exchange reaction with formation of COS and of S ions probably located at the low coordinated sites. It has been found that the basicity of the MgO surface doped with sulfur ions is drastically modified with respect to that of pure MgO [184]. 

Adsorbate pH Adsorbate form Adsorbent s ion exchange capacity (meq/g) Acidic Basic Uptake (mmol/g)... 

Ion Ocean Inventory (10 mol) River Input Atmospheric- Evaporite Cycling S Ion Exchange Hydrothermal Activity Pyrite Burial or Other Carbonate Deposition ... 

A similar mechanism is advanced for the rapid exchange between dissolved sulphur and S ions in polysulphide solutions. The fast exchange between HF and interhalogen fluorides has been accounted for by ionisation ... 

Helfferich, F. Plesset, M.S. Ion exchange kinetics a non-linear diffusion problem. J. Chem. Phys. 1958, 25,411. 

Figure 6.7 X-ray diffractogram of columnar ZnS films obtained after O— S ion exchange, showing that only the sphalerite stmcture is obtained.

Ooi, K., Miyai, Y., and Katoh, S., Ion-exchange properties of ion-sieve-type manganese oxides prepared by using different kinds of introducing ions, Separ. Sci. Technol., 22, 1779, 1987. 

Fig. 1 The ESR spectra of Fe-ZSM-5 samples prepared byconventional (L) and solid-state (S) ion-exchange method.

Inokuti and Hirayama (I-H) (13) developed a quantitative theory of energy transfer by the exchange mechanism and predicted time dependence of fluorescence decay in such coupling. In the 1H approach the S ion is surrounded by a set of A ions at distances RK. 

Once on the chip, the next step is usually some sort of treatment of the sample such that it is made suitable for analysis and detection. Even aqueous samples should be filtered prior to assay. Typically, sample pretreatment takes the form of various fluid handling steps such as concentration flltration ", extractions s , ion exchanges and desaltingS. Combinations and permutations of these steps are also reported. Even degassing can be achieved on chip using ultrasonic-induced cavitations. ... 

Tanaka, K., Ohta, K., and Fritz, J. S., Ion exclusion chromatography of aliphatic carboxylic acids on a cation-exchange resin by elution with polyvinyl alcohol, J. Chromatogr. A, 770, 211-218, 1997. 

Tervonen A, West B, Honkanen S. Ion-exchanged glass waveguide technology A review. Optical Engineering. 2011 50(7) 711071-15. 

The following table summarizes the main economic features of the electrodialysis process to make silica sols in comparison with a plant s ion exchange resin process. 

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