Novel anti-microbial membrane for desalination pretreatment: A silver nanoparticle-doped carbon nanotube membrane

A novel approach was used to synthesize a silver doped-CNT membrane, with the aim of fully utilizing the anti-toxic properties of CNTs and silver. No binder was used for the synthesis of the membrane; instead, silver particles served as a binding material for the CNTs after sintering at high temperature. In the first step, CNTs were impregnated with different loadings of silver (1, 10 and 20 wt.%) via a wet chemistry technique. Impregnated CNTs were then compacted at 200 MPa and sintered at 800 °C for 3 h to form a compact disk (membrane). The powder materials were characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction and thermogravimetric analysis, while the membranes were characterized by measuring their porosity, contact angle, diametrical compression test, pure water permeate flux and antibacterial properties. The affinity of the membranes to biofouling was studied using Escherichia coli (E. coli). The produced membrane showed a high water permeate flux and exhibited strong antibacterial properties. All of the membranes with different silver loadings were able to remove/kill 100% of the bacteria tested; however, the CNT membrane with 10% silver showed a superior performance to the others. All bacteria were removed/killed by the membrane with 10% silver loading after the suspension had passed for only 60 min. These membranes would be advantageous in a continuous filtration system for the removal of different contaminants from water via desalination, adsorption and sieving.