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The inhibition efficiency of a scale inhibitor, named diethylene triamine penta (methylene phosphonic acid) (DTPMPA), was evaluated using fast controlled precipitation (FCP) method, electrochemical quartz crystal microbalance (EQCM), quartz crystal microbalance with dissipation (QCM-D) and pre-scaled quartz crystal microbalance (SQCM). The results showed that DTPMPA delayed the CaCO 3 precipitation and decreased the precipitation rate of the CaCO 3 formation in solution and on a metallic surface, depending on the inhibitor concentration. In some cases, it could completely inhibit CaCO 3 formation. CaCO 3 precipitation was completely inhibited in solution and on a metallic surface in the presence of 0.5 mg⋅L−1 and 4 mg⋅L−1 DTPMPA, according to FCP and EQCM results, respectively. The morphology and composition of CaCO 3 crystals formed were studied using SEM and XRD showing that the presence of the inhibitor promoted the formation of calcite. This is the first time that the influence of an organic inhibitor was studied using the combination of QCM methods, where the results revealed a reduction of the surface coverage by a CaCO 3 layer as the inhibitor concentration increased. The activation energies were calculated in the presence of DTPMPA and indicated that the inhibitor retarded the scaling process. • The scale inhibitor, diethylene triamine penta (methylene phosphonic acid) acts as a nucleation and growth inhibitor. • The inhibition efficiency of DTPMPA was examined for calcium carbonate homogeneous and heterogeneous precipitation. • The inhibition efficiency of DTPMPA increased by varying its concentration from 0.001 to 0.5 mg·L–1. [ABSTRACT FROM AUTHOR]

Chemical antiscalants are usually used to control scale depositions, a major concern in industry. Some of these products may be harmful towards environment or toxic for humans, so environmentally friendly antiscalant are needed. In this respect, plant extracts can be used as new green antiscalant agents. In this work, stock aqueous solution of Herniaria glabra ( H. glabra ) was obtained by infusion. H. glabra is used in traditional medicine to treat or prevent urolithiasis; it could be an interesting candidate as a green antiscaling agent. The properties of H. glabra towards CaCO 3 formation were tested by using chronoamperometry and Fast Controlled Precipitation methods. An n -butanol solution was used to partition the aqueous solution of H. glabra , yielding a polar compounds-free fraction. This fraction was also studied by chronoamperometry and Fast Controlled Precipitation methods. The results showed a better inhibition efficiency towards CaCO 3 precipitation for the n -butanol fraction compared to the crude H. glabra solution. [ABSTRACT FROM AUTHOR]