Format

Send to

Choose Destination
ACS Appl Mater Interfaces. 2019 Apr 17;11(15):14408-14417. doi: 10.1021/acsami.8b22059. Epub 2019 Apr 2.

Understanding the Antifouling Mechanism of Zwitterionic Monomer-Grafted Polyvinylidene Difluoride Membranes: A Comparative Experimental and Molecular Dynamics Simulation Study.

Author information

1
Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry , Chinese Academy of Sciences , Beijing 100190 , People's Republic of China.
2
State Key Laboratory of Organic-Inorganic Composites, College of Chemical Engineering , Beijing University of Chemical Technology , Beijing 100029 , People's Republic of China.
3
Beijing Key Laboratory of Ionic Liquids Clean Process, CAS Key Laboratory of Green Process and Engineering, State Key Laboratory of Multiphase Complex Systems , Institute of Process Engineering , Beijing 100190 , People's Republic of China.

Abstract

The antifouling process of the membrane is very vital for the highly efficient treatment of industrial wastewater, especially high salinity wastewater containing oil and other pollutants. In the present work, the dynamical antifouling mechanism is explored via molecular dynamics simulations, while the corresponding experiments about surface properties of the zwitterionic monomer-grafted polyvinylidene difluoride membrane are designed to verify the simulated mechanism. Water can form a stable hydration layer at the grafted membrane surface, where all the simulated radial distribution function of water/membrane, hydrogen bond number, water diffusivity, and experimental oil contact angles are stable. However, the water flux across the membrane will increase first and then decrease as the grafting ratio increases, which not only depends on the reduced pore size of the zwitterionic monomer-grafted membrane but also results from water diffusion. Furthermore, the dynamical fouling processes of pollutants (taking sodium alginate as an example) on the grafted membrane in water and brine solution are investigated, where both the high grafting ratio and electrolyte CaCl2 can enhance the fouling energy barrier of the pollutant. The results show that both the enhanced hydrophilic property and the electrostatic repulsion can affect the antifouling capability of the grafted membrane. Finally, the ternary synergistic antifouling mechanisms among the zwitterionic membrane, electrolyte, and pollutant sodium alginates are discussed, which could be helpful for the rational design and preparation of new and highly efficient zwitterionic antifouling membranes.

KEYWORDS:

alginates; antifouling mechanism; electrolyte; electrostatic repulsion; molecular dynamics simulation; zwitterionic membrane

PMID:
30895780
DOI:
10.1021/acsami.8b22059

Supplemental Content

Full text links

Icon for American Chemical Society
Loading ...
Support Center