December 2008
ECOSORB® ENGINEERING MANUAL
DISCUSSION Solubility Data: Six studies: 6 mL of various dilutions of Ecosorb 206: 1. 2. 3. 4. 5. 6.
Added 0.9 mL of benzene (note pH of each solution). Added 0.9 mL of benzene and sufficient dilute NaOH to change pH to 7.7. Added 3.0 mL of benzene Added 3.0 mL of benzene and sufficient dilute NaOH to change pH to 7.7. Added 3.0 mL of benzene to soln. made to equal 30% 2-propanol Determined distribution constant ratios of benzene in various concentrations of Ecosorb206.
The following statistical data were calculated: · · · ·
% benzene, standard deviation, confidence limit at 90% confidence level, and coefficient of variation (% relative standard deviation).
When benzene was added, samples were mixed, allowed to stand for 2 hours and the top ¼ to 1/3 removed by aspiration. (to remove un-dissolved benzene from surface). In all cases % benzene in solution increased with an increase in concentration of Ecosorb 206. Graphs contain equation of trend line. The slope is indicative of effect of increasing concentration of 206 as related to total concentration of benzene. When 0.9 mL of benzene was added a larger increase (> slope & % benzene values) occurred when solution was made basic. Basic solutions also had a tighter range (lower CV). No free benzene was observed and it was assumed that solutions were not yet saturated with benzene. When 3.0 mL of benzene was added to 6 mL of solutions an obvious two-layer interface occurred, indicating that an excess of benzene was present. After two hours, the upper ¼ to 1/3 was removed by aspiration. In this study acidic solutions had much greater concentrations of benzene, again indicated by % benzene values and a larger slope. CV values were slightly better in acidic solutions. Solutions containing 30% 2-propanol efficiently dissolved benzene, but with inconsistent results. As Ecosorb 206 concentrations increased, the amount of benzene remaining in solution, compared to benzene released to the environment, increased. Or conversely, as Ecosorb 206 concentrations increase, less benzene is released (a negative slope).
Section 5: Reference Materials
Page 5-63