Thermally efficient hydrophobic zirconia ceramic nanofiber membrane for enhanced membrane distillation performance

The increasing demand for freshwater resources has positioned desalination technologies as essential for sustainable water management. Hence, exploring the applications of membrane distillation (MD) to reduce heat loss and enhance process efficiency becomes crucial in meeting the growing water needs. Zirconia ceramic, with its highly porous structure, high-temperature resistance, and superior heat-insulating properties, plays a significant contribution in the development of low thermal conductivity membranes. This study introduces the fabrication of a low thermal conductivity membrane by integrating flexible zirconia ceramic nanofibers through electrospinning and subsequent calcination. The ceramic composite membrane exhibited a reduced thermal conductivity of 0.044 W m⁻¹ K⁻¹ in contrast to polymer membranes, which is essential for mitigating conductive heat transfer within the membrane. Evaluation of the desalination performance of the ceramic composite membranes revealed a permeate flux of 32.1 LMH for the optimized membrane (f-CPM2) operating with a saline feed solution at 60 °C. Furthermore, investigations of the membrane's heat-insulating properties were enhanced by temperature measurements taken during MD operation and computational fluid dynamics (CFD) analysis. The temperature reduction at the f-CPM2 membrane surface near the outlet demonstrated a slight reduction of only 2.8 %, whereas the polymer membrane exhibited a substantial reduction of 14.7 % relative to the bulk inlet stream temperature. The CFD analysis provided insights into temperature and velocity distribution, enhancing our understanding of thermal efficiency and fluid dynamics within the MD process.