Anti-bacterial assay of doped membrane by zero valent Fe nanoparticle via in-situ and ex-situ aspect

•In-situ fabrication of Fe0-TFN membrane using FeCl3 metal salt and NaBH4.•A comparison of membranes fabricated by in-situ and ex-situ aspects was presented.•Quantitative and qualitative antibacterial analyses of surface imaging were studied.•A new method of evaluation for killing effects of iron nanoparticles was suggested. In this work, two categories of thin film nanocomposite (TFN) membranes have been synthesized via in-situ and ex-situ aspects for grafting biocide Fe0 nanoparticles on the membrane surface. A comparison between ex-situ and in-situ routes also was comprehensively studied. The membrane morphology and surface properties were also studied using contact angle measurements, FT-IR, AFM and SEM, along with desalination performance in terms of water flux and salt rejection. The permeate flux of NaCl solution was 12.93L/m2h for the neat TFC while it was 13.9 and 13.6L/m2h for the TFN obtained in in-situ and ex-situ aspects, respectively. The river water flux recovery of TFN membranes was about 89% in the long term filtration experiments, while it was 71.29% for the neat TFC membrane. To study the anti-bacterial properties of doped membrane, a new method for evaluation the killing effects of iron nanoparticles on bacteria was differently suggested. The results showed good anti-adhesion effects of TFN membrane containing zero-valent Fe nanoparticles on river or seawater natural bacteria.