THE IMPACT OF IONIC STRENGTH UPON INHIBITOR SPECIATION AND EFFICACY

摘要

Previous papers reported observations on the impact of pH, and inhibitor protonation state, on inhibitor efficacy (Ferguson, 2013, Griffiths, 1979, Ramsey, 1985, Tomson, 2002, Hunter, 1993). The data generated in these works is applicable in the low to moderate ionic strength covered. The conditions for the studies did not extend to the high total dissolved solids (TDS) and ionic strength regions encountered in critical current applications for scale inhibition. Water reuse by cooling water systems pushes the operating ion ionic strength well beyond traditional limits, as do other water reuse applications involving reverse osmosis. High TDS studies were conducted in the range of interest to provide insight into scale inhibitor speciation at high ionic strength. pK_a's were measured in solutions "spiked" with NaCl (0 to 200,000 mg/L) to provide data for evaluating scale inhibitor species in high T.D.S. systems. pK_a profiles were developed for commonly applied polymers and phosphonate inhibitors.