In a groundbreaking study conducted by scientists from Yale University and Oak Ridge National Laboratory (ORNL), researchers have unlocked new details in the fight against a costly nuisance facing water treatment facilities: silica scaling. The recent findings offer a clearer path to managing this pervasive issue that plagues industrial systems like reverse osmosis membranes and heat exchangers, through an improved understanding of molecular dynamics.
Commonly, water treatment processes are thrown for a loop trying to contend with the buildup of silica scale – a direct consequence of dissolved silicic acid turning insoluble under specific pH and temperature conditions. Until now, industries have relied on pH adjustments and expensive antiscalants to tackle the problem. These methods are not only costly but they also exacerbate other types of scaling, such as gypsum and calcite. Vyacheslav “Slava” Bryantsev stated, "We know these antiscalants are possibly a class of polyamine-type systems that somewhat impede silica scaling, but how they work and how to improve on their existing properties have been poorly understood," according to ORNL.
Delving into this complexity, the team created nitrogen-containing polymers and tested their effectiveness in an oversaturated silicic acid solution. Notably, the study, titled "Molecular Design of Functional Polymers for Silica Scale Inhibition" and featured in Environmental Science & Technology, demonstrated significant performance variances among similar antiscalant types. Masashi Kaneda of Yale highlighted the unique collaboration, saying, "The approach and the outcome are notable because we provided an understanding of the mechanisms involved in mitigating silica scaling through the use of polymeric antiscalants in water treatment processes."
Through their research, scientists found that polymers with the right mix of charged amine and uncharged amide groups performed exceptionally well in suppressing the formation of silica scale. However, this solution seemingly came easy – the polymer's peculiar functionality to retain reactive silica under neutral pH conditions is largely due to the specific molecular architecture. Digging deeper, the researchers used molecular dynamics simulations to explain why these designed polymers worked where others failed. Deng Dong explained, "We needed to answer why the polymers we designed for the experiment worked, while the monomers did not," as per ORNL.
