A comparative study of novel scale inhibitors with commercial scale inhibitors used in seawater desalination

Seawater from the Arabian Gulf was heated under conditions simulating those of thermal desalination processes and the change in the amount of aquated Ca²+ followed over time using Inductively Coupled Plasma/Optical Emission Spectroscopy. This was done in the absence of any scale inhibitor, and in the presence of scale inhibitors: three commercial polycarboxylate products commonly employed in thermal desalination plants and four novel poly(acrylic acid) inhibitors of differing molar masses and end-group functionality. At times > 2 min, the novel poly(acrylic acid) scale inhibitors of low (~ 2000) molar mass and moderate (hexyl isobutyrate or cyclohexyl isobutyrate) end-group hydrophobicity were more effective in maintaining the aquated Ca²+ level than any commercial product.