Synthesis, Characterisation and Application of Polymeric Scale Inhibitors

Abstract

Desalination of seawater by both the evaporation (e.g. multi stage flash, MSF) and membrane (e.g. reverse osmosis, RO) processes encounters difficulties with precipitation of sparingly soluble inorganic salts such as calcium carbonate (CaCO), magnesium hydroxide (Mg(OH)) and calcium sulfate (CaSO). These precipitate during the desalination process when their solubility product Ksp is exceeded. To control this scaling problem, several methods for scale prevention and control are used, such as acid and additive treatments. Scale inhibitors are chemical additives that have gained importance in controlling scale formation and/or deposition in recent decades. These are low molecular weight organic compounds, typically phosphonates, or polymers of molecular weight 1000-4000, typically containing carboxylate, sulfonate or phosphonate groups.