CFD simulation of channel junction configurations in microfluidic systems: Parametric analysis for sustainable heavy metal extraction and environmental remediation

The integration of liquid-liquid extraction (LLE) and microfluidic technology represents a significant advancement in separation science, particularly for environmental applications such as pollution remediation and resource recovery. This combination addresses key limitations of traditional LLE methods and offers enhanced efficiency, making it a promising approach for sustainable chemical processes. In this study, CFD simulation was conducted to extract Co (II) ions—an environmentally relevant contaminant—using di-2-ethylhexylphosphoric acid (D2EHPA) as the extractant and decane as the solvent phase in a Y-Y microchannel. The influence of various geometrical parameters, such as inlet angle (30-180°) and outlet angle (30-90°), were systematically explored to evaluate their influence on extraction performance. Additionally, Operating conditions included an aqueous phase pH of 4.4-8, an organic-to-aqueous phase flowrate ratio of 0.5-3, an initial Co (II) concentration of 5-25 mM, and an extractant concentration of 10-30 mM were assessed through extensive parametric sweeps. The study revealed that the microchannel's inlet angle significantly affected extraction efficiency, with angles increasing from 30° to 120° leading to enhanced efficiency due to improved phase mixing. The Y-shaped inlet demonstrated superior extraction performance compared to the T-shaped inlet. By analyzing simulation trends and local response surfaces, the most suitable conditions were determined: inlet angle of 132°, outlet angle of 77°, pH of 7.13, initial Co (II) concentration of 21.6 mM, extractant concentration of 27.2 mM, and flow rate ratio of 2.53. Under these conditions, an extraction efficiency of 84.46 % was achieved. These findings highlight the potential of microfluidic LLE systems for environmental applications, including the remediation of heavy metal pollution, improved separation efficiency in sustainable mining operations, and the development of eco-friendly lab-on-a-chip technologies for rapid, small-scale environmental monitoring.