Effects of additives on dual-layer hydrophobic-hydrophilic PVDF hollow fiber membranes for membrane distillation and continuous performance

► Application of dual-layer hydrophobic-hydrophilic hollow fiber membranes in MD is proven advantageous. ► Incorporation of methanol additive improves membrane stability under continuous MD operation. ► Addition of methanol transforms the morphology from porous agglomerated globule into denser interconnected globule. ► Membrane hydrophobicity is enhanced with FSi particles additive. ► The existence of the hydrophilic hydroxyl group on the surface of FSi particles may induce membrane wetting.