Antibiofouling Polyvinylidene Fluoride Membrane Modified by Quaternary Ammonium Compound: Direct Contact-Killing versus Induced Indirect Contact-Killing.
Widespread applications of membrane technology call for the development of antibiofouling membranes. For the traditional contact-killing strategy, the antibacterial action is restricted to the surface: the membrane loses its antibiofouling efficacy once its surface is completely covered with a fouling layer. However, in this study, polyvinylidene fluoride (PVDF) microfiltration membranes blended with quaternary ammonium compound (QAC) exhibited a surprisingly lasting antimicrobial activity in the vicinity of the membrane surface. The results indicated that QAC was capable of driving surface segregation with a high structural stability, and the QAC modified membrane shows clear antibacterial effects against both Gram-positive and Gram-negative bacteria. Covering the modified membrane surface by an abiotic alginate layer resulted in a loss of antibacterial efficiency by 86.2%. In contrast, the antibacterial efficiency was maintained after developing a biofilm of Staphylococcus aureus of 30 μm in thickness. The current study may suggest that bacteria affected by contact-killing might interact with other bacteria in the vicinity, resulting in retarded biofilm growth. The antibiofouling effect and associated mechanism of the QAC modified membrane were further validated in a membrane bioreactor during long-term operation.
State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University , 1239 Siping Road, Shanghai 200092, China.
Xingran
X
Zhang
State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University , 1239 Siping Road, Shanghai 200092, China.
Jinxing
J
Ma
Department of Civil Engineering, The University of Hong Kong , Pokfulam, Hong Kong, China.
Chuyang Y
CY
Tang
State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University , 1239 Siping Road, Shanghai 200092, China.
Zhiwei
Z
Wang
Centre for Water Research, Department of Civil and Environmental Engineering, National University of Singapore , 1 Engineering Drive 2, Singapore 117576, Singapore.
How Yong
HY
Ng
State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University , 1239 Siping Road, Shanghai 200092, China.
Zhichao
Z
Wu
D000900:Anti-Bacterial Agents / Q000494:pharmacology; D018441:Biofilms / Q000187:drug effects; D006090:Gram-Negative Bacteria; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D013211:Staphylococcus aureus / Q000187:drug effects*
D000900:Anti-Bacterial Agents; D000644:Quaternary Ammonium Compounds