Controlling calcium carbonate scaling in desalination: A green approach using citric acid

This study focuses on the deposition of calcium carbonate, adding citric acid in solution: it shows green properties and can retard scale precipitation, reducing equipment malfunctions. Three concentrations were considered (0.520×10−3, 1.041×10−3, 1.561×10−3mol/l), with different temperature values (15°C, 35°C). Results showed that citric acid is a powerful retarding agent, enhancing this behaviour at 15°C. Moreover, it makes nucleation more difficult because it can increase the interfacial tension between CaCO3 crystals and the surrounding solution. Finally, citric acid favors the formation of calcite crystals with reduced sizes, whose morphological characteristics hinder their growth.