Zirconium dioxide membranes decorated by silanes based-modifiers for membrane distillation – Material chemistry approach
Résumé
Zirconium dioxide membranes (3 nm and 200 nm) were chemically modified by silane-based modifiers with
different degrees of fluorination. Comprehensive material characterization has been performed before and after
the modification process by goniometric, and microscopic techniques. Wetting properties has been accomplished
by applying the Zisman method, Kao diagram, spreading pressure, and critical surface tension. The mechanical,
tribological, and separation features of all membranes were investigated as a function of grafting time for 5h,
15h, and 35h.The performance of the membrane was assessed in air-gap membrane distillation processes. Nonfluorinated membranes possessed better transport properties and better mechanical stability in comparison with
fluorinated ones which enable the generation of porous, hydrophobic, crack-free material, optimized for MD.
Grafting with short fluorocarbon chains (FC6) produced highly hydrophobic materials (CA ¼ 145�) with low
roughness (Rq ¼ 6.58 nm) compared to grafting with long fluorocarbon chains (FC12). On the other hand, FC6
showed a highly permeable character and elimination of problems related to substantial flux reduction and pore
blocking.
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