Predicting and evaluating the performance of DCMD: The effect of non-ideal morphology and thermal conductivity of porous nanocomposite membranes

The aim of this work is to explore the effects of the factors affecting the thermal con-ductivity of the porous nanocomposite membranes and their performance in direct contact membrane distillation (DCMD). The thermal conductivity models were evaluated comprehensively for membrane material involving three-phases (filler particle, polymer and interface). Hashemifard-Matsuura-Fauzi (HMF) and Maxwell models were the most reliable models among three-phase and two-phase (nanocomposite material and pores) models, respectively. Thus, the thermal conductivity of the porous nanocomposite membrane was obtained by the combination of three-phase HMF and two-phase Maxwell model. Finally, the performances of PTFE/Silica aerogel (SiAG) and PTFE/CaCO3 porous nanocomposite membranes were disclosed by the heat and mass transfer model in a DCMD system in order to study the effects of particle loading, interlayer thickness and membrane porosity. It was concluded that both membrane thermal conductivity and the DCMD flux approach almost the same values at the high end of interface thickness, re-gardless of the thermal conductivity of the filler particle. In other words, the heat loss of the system can be controlled by tuning the interface thickness in order to achieve a high DCMD flux even by incorporating fillers with higher thermal conductivity rather than that of the pure polymer. In summary, our findings revealed that next to the membrane ma-terial and porosity, the type of the nanoparticle and interface thickness can be highlighted as the most important parameters for controlling membrane thermal conductivity and improving DCMD performance.(c) 2023 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.