Silver nanoparticle-decorated porous ceramic composite for water treatment

Silver nanoparticle-decorated porous ceramic composites have been prepared by overnight exposure to a sliver nanoparticle colloid solution of a porous ceramic modified by an aminosilane coupling agent, 3-aminopropyltriethoxysilane (APTES). The connection between the nanoparticle and the ceramic relies on the coordination bonds between the –NH2 group at the top of the APTES molecule and the silver atoms on the surface of the nanoparticles. The other end of the aminosilane coupling agent attaches to silicon atoms in the ceramic through a Si–O–Si bond. There is no obvious loss of nanoparticles after immersion in an ultrasonic bath for 15 min, or after keeping the treated ceramic for several weeks in an atmospheric environment. On-line tests were conducted with a mimetic water filter. At a flow rate of 0.01 L/min, the output count of Escherichia coli was zero when the input water had a bacterial load of ∼105 colony-forming units (CFU) per millilitre. Combined with low cost and effectiveness in prohibiting the growth of E. coli, such materials should have wide application to drinking water treatment.