2. Materials and experimental methods
2.1. Materials
A commercial polyamide RO membrane was obtained from Nitto Denko Corporation (ES20; Osaka, Japan). The mean surface roughness(Ra) of this RO membrane was 97.1 nm from atomic force microscope(AFM) observation (Fig. S1, details in Supplementary data), and was a typical value of RO membranes [8]. Fe (III)–EDTA was purchased from Dojindo Laboratories (Kumamoto, Japan). A LIVE/DEAD BacLight Bacterial Viability kit was purchased from Thermo Fisher Scientific (Waltham, MA) and used to stain bacteria. All chemicals, except those particularly described, were purchased from Wako Pure Chemical Industries(Osaka, Japan) and used without further purification. Milli-Qwater (18.2 MΩ·cm; Merck Millipore, Billerica, MA, USA) was used to prepare all aqueous solutions and for rinsing.