Concentrated, Mixed-Salt Solutions

Salts, Mixed Solution Dilute Solution)—Iraaskr 10.0 mL of the concentrated mixed salts solution into a 1000-mL volumetric flask and dilute to the mark with mixed alcohol solvent. 

Stabilisation by climate control. The most desirable method to prevent damage induced by the repeated cycles of crystallisation and hydration would probably be environmental control. However, neither the selection nor the maintenance of such an ideal environment is possible if looked at realistically. Predictions of salt crystallisation and hydration from mixed salt solutions are more or less impossible, taking into account all the different parameters that influence the process. Sawdy provides a brilliant overview of the subject and considers relative humidity, temperature, air movement, type and structure of the porous support, salt mixture composition and salt concentration. It is necessary to consider not only consolidation treatments of the plaster or the paint layer, which as such may influence the transition behaviour of the salts, but also the influence of microbial extracellular slimes on the porosity of the system. 

When an ion exchange membrane is equilibrated with a mixed salt solution, the ratio of ions in the membrane phase attains an equilibrium, as for an ion exchange resin.20 The preference of the ion exchange membrane for one of the two counterions is expressed by a separation factor, a , in which the concentration of ions is expressed by equivalent,... 

Figure 5.2 compares the change in PNaCa of a phosphonic acid membrane and that of a sulfonic acid membrane with the concentration of the mixed salt solution when 1 1 mixed salt solutions composed of calcium chloride and sodium chloride of various concentrations were electrodialyzed.26 PNaCa of the phosphonic acid membrane is lower than that of the sulfonic acid membrane. Transport numbers of all alkaline earth metal cations relative to sodium ions for the phosphonic acid membrane are also lower than those of the sulfonic acid membrane.26 However, the current efficiency of the phosphonic acid membrane was about 10% lower than that of the sulfonic acid membrane. Alkaline earth metal cations more... 

Figure 5.2 Comparison of transport number of calcium ions relative to sodium ions in a phosphonic acid membrane with that in a sulfonic acid membrane. ( ) sulfonic acid membrane (A) phosphonic acid membrane. 1 1 mixed salt solutions of calcium chloride and sodium chloride of different concentrations were electrodialyzed.

Figure 5.10 Change in transport number of calcium ions relative to sodium ions of a cation exchange membrane with and without a polypyrrole layer with the concentration of mixed salt solutions in electrodialysis. (A) Cation exchange membrane, NEOSEPTA CM-1 (O) membrane with a polypyrrole layer facing the anode side (X) membrane with polypyrrole layer facing the cathode side. After one surface of the cation exchange membrane (Fe3+ form) had contacted an aqueous pyrrole solution for 4 h, the membrane was immersed in LON hydrochloric acid solution before equilibration with the mixed salt solution used in electrodialysis.

Figure 5.12 Change in transport number of calcium ions relative to sodium ions (PNaCa) and current efficiency of a cation exchange membrane with polyaniline layers on both sides with polymerization time. After the cation exchange membrane, NEOSEPTA CM-1, had been immersed in an aqueous 10% aniline hydrochloride solution for 24 h and then immersed in a 1.0 N ammonium peroxodisulfate solution for various periods, a 1 1 mixed salt solution of 0.250 N calcium chloride and 0.250 N sodium chloride solution (concentration of chloride ions 0.500 N) was electrdodialyzed at 10Acm 2 for 60 min at 25.0 °C.

Figure 5.14 Change in ratio of calcium ions to sodium ions in the membrane phase during electrodialysis (KNaCa) with polymerization time of aniline. After a 1 1 mixed salt solution of 0.250N calcium chloride and 0.250N sodium chloride (concentration of chloride ions 0.500N) had been electrodialyzed for 1.0 h at 10 mA cm 2 using a membrane with polyaniline layers, the membrane was immediately removed from the cell during electrodialysis and the ratio of calcium ions to sodium ions in the membrane phase was determined (starting membrane NEOSEPTA CM-1).

Figure 5.21 Change in transport number of nitrate ions relative to chloride ions with the number of methylene groups of a, co-diamines. ( ) Concentration of Na+, 0.01 N (A) concentration of Na+, 0.04 N. The transport number of nitrate ions relative to chloride ions was measured using a 1 1 mixed salt solution of sodium nitrate and sodium chloride (concentration of sodium ions 0.01 or 0.04 N) at a 0.10 mA cm 2 for 60 min at 25.0 °C under vigorous agitation.

Figure 5.23 Change in transport number of fluoride ions relative to chloride ions with concentration of mixed salt solution. (O) cross-linkage, 10% ( ) cross-linkage, 14% (X) cross-linkage, 20%. Dotted line anion exchange membranes reacted with 4-vinylpyridine for 48 h and then with trimethylamine for 24 h solid line anion exchange membranes reacted with only trimethylamine. Electrodialysis of 1 1 mixed solutions of sodium fluoride and sodium chloride was carried out for 60 min at 25.0 °C.

Figure 5.26 Relationship of Pa50 to the concentration of 1 1 mixed salt solutions of sodium sulfate and sodium chloride using anion exchange membranes with and without anionic polyelectrolyte layers. (O) without the layer ( ) immersed in 1000ppm poly(styrene sulfonic acid) (reduced viscosity of 1.0% solution, r sp/C 0.714 dlg ) solution (X) with 1000ppm polycondensation product of sodium naphthalene sulfonate and formaldehyde (MW ca. 1000) solution. After an anion exchange membrane (NEOSEPTA AM-1 strongly basic anion exchange) had been immersed in the anionic polyelectrolyte solution for 17 h at 25.0 °C, 1 1 mixed salt solutions of sodium sulfate and sodium chloride were electrodialyzed for 60 min at 25.0 °C under vigorous agitation.

Figure 5.39 Change in transport numbers of bromide, nitrate and sulfate ions relative to chloride ions in anion exchange membranes reacted with various amines. ( ) trimethylamine (H) ethylenediamine and then trimethylamine until electrical resistance of the membrane attained was ca. 10 Qcm2 (2 h) (3) tetraethyle-nepentamine and then trimethylamine until the resistance attained was ca. 10 Qcm2 (32 h) ( ) polyethyleneimine and then trimethylamine until the resistance attained was ca. 10 Qcm2 (64 h). The membranes were immersed in 1.0 N hydrochloric acid solution for 2 h before electrodialysis and PaA was measured by electrodialysis of 1 1 mixed salt solutions (concentration of sodium ions 0.04 N) at 1.0 mA cm 2 at 25.0 °Cfor 60 min.

---