A porous carbon foam electrode (CF) modified with reduced graphene oxide-Ag (rGO-Ag) nanocomposite has been fabricated to purify water. It can perform as an antibacterial device by killing pathogenic microbes with the aid of a 1.5 V battery with very little power consumption. The device is recycled for ten times with good performance for long term usage. In other words, the device may be implemented as fast water purifier to deactivate the pathogens in drinking water.

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Copper encapsulated polystyrene nanocomposite particles were prepared through ex-situ dispersion of Cu nanoparticles into monomer droplets and subsequent polymerization using water-in-sc-CO2 at 70oC. First, colloidal dispersion of copper nanoparticles were synthesized by chemical reduction of copper chloride (CuCl2) using sodium borohydrate (NaBH4) as reducing agent. Colloidal dispersion of copper nanoparticles was added slowly during the polymerization of styrene using water-in-sc-CO2 medium at 70oC and 20.68 MPa. Cu nanoparticle encapsulated polymer particles were characterized by UV, XRD, TGA, SEM and TEM. Cu nanoparticles were uniformly distributed inside the polymer matrix during the polymerization process. This work represents a simple way to prepare a variety of metal nanoparticles encapsulated polymer particles using water-in sc-CO2 medium. The Cu/polystyrene nanocomposite particles exhibit antimicrobial activity against a number of bacteria. The current work represents a simple and universal way to prepare a variety of metal–polymer nanocomposite materials.