Development of a novel perfluoropolyether (PFPE) hydrophobic/hydrophilic coated membranes for water treatment

• Published in: Journal of membrane science 2019-07, Vol.581, p.58-71
• Main Authors: Ursino, C., Di Nicolò, E., Gabriele, B., Criscuoli, A., Figoli, A.
• Format: Article
• Language: English
• Subjects: DCMD; Desalination; Membrane preparation; PFPE Fluorolink® coating; Salt rejection
• ISSN: 0376-7388; 1873-3123
• DOI: 10.1016/j.memsci.2019.03.041

A novel method to prepare hydrophilic/hydrophobic membranes via dip-coating and UV in situ polymerization was presented. Fluorolink® MD700, a UV-curable perfluoropolyether (PFPE) hydrophobic compound, was employed as surface modifier via coating technique on two different commercial hydrophilic membranes with different pore size (0.1-0.2-0.45 μm): polyamide (PA), and polyethersulfone (PES). The influence of starting membrane material (PA-PES) was studied and all coated membranes were characterized in terms of surface morphology, water and oil contact angle, porosity, pore size, liquid entry pressure and mechanical tests. The coating resistance and stability in time with salty solution NaCl 0.6 M and chemicals cleaning agents, such as KMnO4 0.1 wt%, Hypochlorite NaClO pH 4.25, HCl pH 2.5, NaOH pH 11.5, were evaluated. Membranes performance was tested in direct contact membrane distillation (DCMD) configuration, using deionized water and salty solution 0.6 M (NaCl) as feed. The effect of the starting material on the permeate fluxes was investigated. The measured permeate water fluxes ranged between 3 and 22 kg/m2h and 2.9–19.5 kg/m2 h for PA and PES respectively, at different feed temperatures (40–60 °C). Both flux (∼8.3 kg/m2 h) and salt rejection (∼99.95%) were kept constant during a prolonged test (158 h) carried out at 50 °C on the coated PA 0.45 μm membrane. [Display omitted] •Perfluoropolyether compound (PFPE) was employed as monomer for surface modification.•Membranes were prepared via dip-coating/in situ polymerization using UV-curable PFPE.•Hydrophilic/hydrophobic and oleophobic composite membranes were prepared.•Polyamide (PA) and polyethersulfone (PES) as starting materials have been employed.•New coated membranes are successfully applied in membrane distillation applications.