title: Molecular Grafting of Fluorinated and Nonfluorinated Alkylsiloxanes on Various Ceramic Membrane Surfaces for the Removal of Volatile Organic Compounds Applying Vacuum Membrane Distillation.
abstract: Four main tasks were presented: (i) ceramic membrane functionalization (TiO25 kDa and 300 kDa), (ii) extended material characterization (physicochemistry and tribology) of pristine and modified ceramic samples, (iii) evaluation of chemical and mechanical stability, and finally (iv) assessment of membrane efficiency in vacuum membrane distillation applied for volatile organic compounds (VOCs) removal from water. Highly efficient molecular grafting with four types of perfluoroalkylsilanes and one nonfluorinated agent was developed. Materials with controllable tribological and physicochemical properties were achieved. The most meaningful finding is associated with the applicability of fluorinated and nonfluorinated grafting agents. The results of contact angle, hysteresis of contact angle, sliding angle, and critical surface tension as well as Young's modulus, nanohardness, and adhesion force for grafting by these two modifiers are comparable. This provides insight into the potential applicability of environmental friendly hydrophobic and superhydrophobic surfaces. The achieved hydrophobic membranes were very effective in the removal of VOCs (butanol, methyl-tert-butyl ether, and ethyl acetate) from binary aqueous solutions in vacuum membrane distillation. The correlation between membrane effectiveness and separated solvent polarity was compared in terms of material properties and resistance to the wetting (kinetics of wetting and in-depth liquid penetration). Material properties were interpreted considering Zisman theory and using Kao diagram. The significant influence of surface chemistry on the membrane performance was noticed (5 kDa, influence of hydrophobic nanolayer and separation controlled by solution-diffusion model; 300 kDa, no impact of surface chemistry and separation controlled by liquid-vapor equilibrium).
authors.affiliation: Faculty of Chemistry, Nicolaus Copernicus University in Toruń , 7 Gagarina Street, 87-100 Torun, Poland.
authors.forename: Joanna
authors.initials: J
authors.lastname: Kujawa
authors.affiliation: Pharmaceutical and Chemical Engineering Department, German-Jordanian University , Amman 11180, Jordan.
authors.forename: Samer
authors.initials: S
authors.lastname: Al-Gharabli
authors.affiliation: Faculty of Chemistry, Nicolaus Copernicus University in Toruń , 7 Gagarina Street, 87-100 Torun, Poland.
authors.forename: Wojciech
authors.identifier: http://orcid.org/0000-0001-8020-8108
authors.initials: W
authors.lastname: Kujawski
authors.affiliation: Faculty of Chemistry, Nicolaus Copernicus University in Toruń , 7 Gagarina Street, 87-100 Torun, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Knozowska
keywords: ceramic functionalization; ceramic membranes; hydrophobicity; vacuum membrane distillation; volatile organic compounds