Ultrapure water density

Table 12.1 Density of ultrapure water (UPW) at various temperatures (units are g/mL, temperature is in degrees Celsius)... 

The solubility of crystalline AgCl in ultrapure water has been determined from the electrical conductivity of the saturated solution. " The average of five measurements at 298.15 K is sb = 1.337 X 10 moldm . The density of water at this temperature is pX = 0.9970kg dm . ... 

FIGURE 8.11 Effect of 3 mM solution of Ch (gray line) and ultrapure water (black line) on the cell voltage of a PEM EC single cell. Cell temperature = 80°C, operating current density = 300 mA cm" anode humidification = 70°C, cathode humidification = 30°C. (Reprinted from Journal of Power Sources, 179, Matsuoka, K. et al. Degradation of polymer electrolyte fuel cells under the existence of anion species, 560-565, Copyright (2008), with permission from Elsevier.)... 

The colloid solutions described above (Ag nanotriangles, citrate-reduced Ag, and citrate-reduced Au) were dialyzed against pH=5 ultrapure water for 48 hours before further modification. Based on the known size and density of the metallic cores, 1 mM aqueous (3-aminopropyl)trimethoxysilane (390 iL) was added to 10 mL of the dialyzed colloid solution. After 15 minutes, the pH of the colloid/(3-aminopropyl)trimethoxy-silane solution was raised to 11.5 by adding aqueous potassium hydroxide. Finally, the silica shell began to form after 27% sodium silicate (2.1 xL) was added to the basic solution. Quenching of the shell growth was accomplished by adding 40 mL of absolute ethanol to the nanoparticle solution. 

The volume fraction of the initial stock solution, ( ) = clp a l a - b )] == 0.12, is estimated from the lipid concentration c used in the preparation by assuming that the thickness and the density of the phospholipid shell are respectively a-b = A nm and = 1.015 g/cm [14-16] a and b are respectively the outer and inner radius of the vesicle. Additional suspensions with volume fractions ranging from ( ) 0.009 to ( ) 0.12 are prepared by diluting the stock solution with ultrapure water. 

Brine and soft water of ultrapure quality is essential for smooth and efficient operation of membrane cell process since Ca2+ and Mg2+ ions can harm the performance of ion-exchange membranes in the following ways. The precipitated Ca(OH)2 and Mg(OH)2 offer increased electrical resistance across the membrane thereby increasing the cell voltage. Furthermore, the anolyte diffusion layer characteristics are affected which would alter the optimum current density. More seriously, the membrane performance is affected... 

---