Green Anti-scalent for Cooling Water Systems

摘要

The effect of Punica granatum hull and Punica granatum leaf extracts as green inhibitors for theformation of calcium carbonate scale have been investigated using conductivity measurements,electrochemical impedance spectroscopy (EIS), and chronoamperometry techniques in conjunctionwith the scanning electron microscopy (SEM), energy- dispersive x-ray analysis (EDX) and opticalmicroscopic examinations. Mineral scales were deposited from the brine solution by cathodicpolarization of the steel surface. The results showed that the anti-scaling property of the extracts couldbe attributed to the presence of ellagic acid. In solution, ellagic acid retards calcium carbonateprecipitation via formation of a complex with the calcium cations. Thin, smooth and non adherent filmformed over the steel surface, under cathodic polarization, by the deposition of the calcium-ellagatecomplex. The hull extracts were found to exhibit better anti-scalant properties than Punica granatumleaf extract. The stability of the aqueous extracts with time was also investigated.