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In this study, fast controlled precipitation (FCP) and chronoamperometry (CA) methods were performed to evaluate the influence of the magnetic treatment at 0.70 T, upon the scale formation in synthetic solutions (hardness 25 °F), exposed to a static magnetic field for different exposure times. According to FCP results, homogeneous CaCO3 precipitation rates in treated solution were lower than those in the absence of the magnetic field. It has been found that the memory effect can last up to 24 h after the magnetic treatment even if it decreases over time. As purpose of comparison, CA method was applied to investigate the influence of the magnetic treatment on heterogeneous CaCO3 precipitation. The magnetic field effect increased with the increasing exposure time. The obtained scale, characterized by scanning electronic microscopy and X‐ray diffraction, was formed by a mixture of calcite and aragonite in the presence of magnetic field. [ABSTRACT FROM AUTHOR]

Abstract In this study, fast controlled precipitation (FCP) and chronoamperometry (CA) methods were performed to evaluate the influence of the magnetic treatment at 0.70 T, upon the scale formation in synthetic solutions (hardness 25 °F), exposed to a static magnetic field for different exposure times. According to FCP results, homogeneous CaCO3 precipitation rates in treated solution were lower than those in the absence of the magnetic field. It has been found that the memory effect can last up to 24 h after the magnetic treatment even if it decreases over time. As purpose of comparison, CA method was applied to investigate the influence of the magnetic treatment on heterogeneous CaCO3 precipitation. The magnetic field effect increased with the increasing exposure time. The obtained scale, characterized by scanning electronic microscopy and X‐ray diffraction, was formed by a mixture of calcite and aragonite in the presence of magnetic field.

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]

Scaling process is the main problem encountered in industrial plants using water. Several factors (pH, temperature, hydrodynamic conditions, metal surface, and especially, water composition) can affect the scaling kinetics of calcium carbonate (CaCO3), one of the main components of scaling. In addition, some foreign ions added can considerably modify the scaling rates. In this work, the inhibiting effects of Zn2+ and Cu2+ cations on CaCO3 precipitation were studied in a 50°F synthetic carbonic solution by using fast controlled precipitation (FCP) and scaling quartz crystal microbalance (SQCM) methods, for homogeneous and heterogeneous scaling deposition, respectively. Results showed that Zn2+ and Cu2+ ions are efficient, at high concentrations (=1 mg/L), to delay or even to prevent nucleation/growth of CaCO3. FCP measurements showed a complete inhibition of the homogeneous CaCO3 precipitation after 120 min in synthetic solution containing 5 and 4 mg/L of Cu2+ and Zn2+, respectively. SQCM measurements showed that the surface coverage of the metallic substrate by a layer of CaCO3 is reduced when the amount of these cations increased. Zn2+ cations inhibited the heterogeneous CaCO3 precipitation more efficiently than Cu2+. SEM and XRD results indicated that both cations affect calcium carbonate nucleation by changing the morphology of CaCO3 crystals. [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]