Enhanced performance of novel nano-enabled PVDF membranes with amino and chloro-based clay for membrane distillation

Recent advancements in membrane distillation have prompted considerable interest in enhancing polymeric membrane performance through various surface modification processes. In this study, we reported the synthesis of novel polyvinylidene fluoride (PVDF) composite membranes composed of amino (Am(2)-SCA) and chloro-based (Ch-SCA) clay nanoparticles (CNPs). The sol–gel chemical method was used to synthesize the CNPs, and the composite membranes were fabricated from amino-based CNPs (i.e., hydrophilic membranes) and chloro-based CNPs (i.e., hydrophobic membranes), with the addition of various compositions of the CNPs in the PVDF polymer matrix. The performance of the developed membranes was evaluated by air gap membrane distillation (AGMD) using a highly saline feed solution (70 gL⁻¹ NaCl). The inclusion of CNPs in the polymer significantly improved the performance of PVDF membranes. Notably, the hydrophobic composite membranes demonstrated excellent performance with high flux and stable rejection, while the hydrophilic composite membranes exhibited moderate permeation flux at lower CNPs concentrations (0.50 wt%) and higher flux with a corresponding decrease in rejection as the concentration increased. The composite membrane containing 1 wt% hydrophobic CNPs displayed the best AGMD performance with a permeate flux of 12.80 kg m⁻² h⁻¹ and 99.99 % salt rejection. The superior performance of the composite membranes was ascribed to the effective dispersion of CNPs in the membrane matrix and improved membrane properties suitable for efficient desalination in MD.