Water-soluble sulfonated polyaniline as multifunctional scaling inhibitor for crystallization control in industrial applications

The assessment of the water-soluble sulfonated polyaniline (SPANI) as a new scale inhibitor of CaCO3 and CaSO4 using slandered NACE, electrochemical tests and microscopic examinations was the main objective of this work. The adsorption properties of the scale inhibitor were investigated using adsorption isotherms. Results showed that SPANI is an efficient new inhibitor in controlling the precipitation of calcium carbonate and calcium sulfate scales. The inhibitory effect of SPANI can be attributed to interaction of calcium with the polymer backbone via (Ca. . .SO3) coordination which disturb the normal crystal growth of scales on solutions. The molecular interaction constant depends on charges at the hydrophilic sulfonates head as well as steric entanglement of polymer chains. Furthermore, adsorption isotherms prove that the inhibitory effect of SPANI can be also attributed to the presence of negative charge on the polymer backbone which facilitates the attachment of polymer molecules on metal surface which hinder attachment of scale crystals on it. It can be concluded that SPANI alters the growth mechanisms of the crystals in solutions, as well as it change the potential of scales to attach equipment surface. (C) 2021 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.