关键词: nitrification;biofilter;carbon foam;purification of nitrogen oxides;air pollution control

Abstract: Carbon foam-a kind of new engineering material as packing material was adopted in three
biofilters with different pore dimensions and adapted autotrophic nitrite nitrobacteria to
investigate the purification of nitric oxide (NO) in a gas stream. The biofilm was
developed on the surface of carbon foams using nitrite as its only nitric source. The
moisture in the filter was maintained by ultrasonic aerosol equipment which can minimize
the thickness of the liquid film. The liquid phase nitrification test was conducted to
determine the variability and the potential of performance among the three carbon foam
biofilters. The investigation showed that during the NO-2-N inlet concentration of 200 g-L
-1 .min-1 to 800 g-L-1 .min-1, the 24PPC (pores per centimeter) carbon foam biofilter had
the greatest potential, achieving the NO-2-N removal efficiency of 94% to 98%. The 8PPC and
18PPC carbon foam biofilters achieved the NO-2-N removal efficiency of 15% to 21% and of
30% to 40%, respectively. The potential for this system to remove NO from a gas stream was
shown on the basis of a steady removal efficiency of 41% to 50% which was attained for the
24PPC carbon foam biofilter at specified NO inlet concentration of 66.97mg.m-3to 267.86
mg.m-3 and an empty-bed residence time of 3.5 min.

Key words: nitrification, biofilter, carbon foam, purification of nitrogen oxides, air pollution control