Modified macromolecules in the prevention of silica scale

Silicic acid polycondensation leads to the formation of amorphous silica. This process is of great importance to the survival of certain living organisms, such as diatoms and sponges, but presents a significant problem in various production facilities that use water for heating or cooling. In the latter, amorphous silica can be a recalcitrant deposit that can hamper proper system operation. Hence, inhibition of silicic acid polycondensation by chemical inhibitors is an intensely sought strategy by water system operators. In this manuscript, we report the inhibitory effect of zwitterionic phosphonated analogs (PPEI’s) of the cationic polymeric chemical additive polyethyleneimine (PEI) in mildly supersaturated silica solutions (500 ppm/8.3 mM “Si”) at pH=7. The inhibition efficiency of PPEI’s depends on a variety of parameters, such as concentration and degree of phosphonomethylation of the parent PEI polymer.