A comprehensive study on the impact of electromagnetic fields on calcium carbonate scaling in membrane distillation

Here the impact of electromagnetic field (EMF) on CaCO₃ scaling during membrane distillation (MD) was examined. Synthetic feed solutions with varying salinities (0 to 35,000 mg/L of NaCl concentration), different scaling potential index (SPI = 3.28 and 3.81), and natural seawater were used. Key parameters such as conductivity, Ca²⁺ and alkalinity concentrations, permeate flux, and the amount of CaCO₃ formed were monitored throughout the experiments. Furthermore, the morphology of CaCO₃ was examined by employing a scanning electron microscope (SEM) and X-ray powder diffraction (XRD). The results demonstrated that integrating an EMF device, generating a maximum intensity of 25 mT, significantly improves permeate flux by enhancing water evaporation and reducing CaCO₃ surface crystallization across all the test conditions. The EMF exposure promotes bulk crystallization, accelerates of phase transformation of CaCO₃, reduces of crystal size, and alters crystal structure. Notably, at high salinity (35,000 mg/L), the formation of a new phase of coprecipitation orthorhombic Nyerereite (Na₂Ca(CO₃)₂ was experimentally detected, suggesting the role of EMF on activation of ions and co-precipitation reaction. These findings demonstrate that EMF integration into MD systems is a promising and cost-effective strategy for scaling remediation, with a potential applications in industrial desalination and water treatment.