Air purification equipment combining a filter coated by silver nanoparticles with a nano-TiO2 photocatalyst for use in hospitals
Thanh Son Le, Trong Hien Dao, Dinh Cuong Nguyen, Hoai Chau Nguyen and I L Balikhin
Abstract
X-ray diffraction, scanning electron microscopy and transmission electron microscopy showed that TiO2 particles synthesized by a sol–gel procedure exhibited uniform size about 16–20 nm. This nanopowder was deposited on a porous quartz tube (D = 74 mm, L = 418 mm, deposit density ~16.4 mg cm−2) through an intermediate adhesive polymethylmethacrylate layer to manufacture a photocatalytic filter tube. A polypropylene pre-filter was coated with a nanosilver layer (particle size ~20 nm) prepared by aqueous molecular solution method. An air cleaner of 250 m3 h−1 capacity equipped with this pre-filter, an electrostatic air filter, 4 photocatalytic filter tubes and 4 UV-A lamps (36 W) presented the high degradation ability for certain volatile organic compounds (VOCs), bacteria and fungi. The VOCs degradation performances of the equipment with respect to divers compounds are different: in a 10 m3 box, 91.6% of butanol was removed within 55 min, 80% of acetone within 100 min, 70.1% of diethyl ether within 120 min and only 43% of benzene was oxidized within 150 min. Over 99% of bacteria and fungi were killed after the air passage through the equipment. For application, it was placed in the intensive care room (volume of 125 m3) of E hospital in Hanoi; 69% of bacteria and 63% of fungi were killed within 6 h
