Influence on the Magnetic Field on the Scale Formation in a Microfluidic Channel under A Low Reynolds Number Flow

Abstract

Abstract This study presents an external magnetic array to rapidly investigate the calcium carbonate formation in a microfluidic channel. The system was made by a copper coil capillary as the heat exchanger, a high-precision thermostatic water tank, a magnetic drive pump, and an external magnetic array. Different concentrations (3 mM and 10 mM), magnetic treated efficiency (magnet length 4.0 cm and 14.0 cm, treatment time 24 hr and 72 hr), and temperature (25oC to 50oC) of test solution were discussed during the experiment. The concentration of calcium ion, electrical conductivity, and pH value were measured to record the subtle change during water treatment. In addition, the SEM and the XRD were used to analyze the particle size distribution and morphology of calcium carbonate under different magnetic treatments. As the results of the experiments, (1) the particle size of calcium carbonate decreased when a magnetic field was applied to the solution in a microfluidic channel under a low Reynolds number flow, (2) the aragonite didn’t appear in the microfluidic channel, and (3) the physicochemical properties of the solution weren’t altered by the magnetic treatment. Consequently, the small particle size can inhibit microchannel from blocking, and the outcome of this study provides an alternative method to minimize the scale problem in micro heat exchangers.