Removal of air pollutants in the make-up air of a semiconductor plant by fine water spray

Abstract

This study presented a fine water spray technique to remove acidic/basic gas particulate from the make-up air of a semiconductor manufacturing plant. The concentration of air pollutants was measured at the inlet and the outlet of the device with the help of HDS (Honeycomb Denuder System) samplers followed by sample analysis. Results show that the removal efficiency of the fine water spray device for gas pollutants, i.e., HF, HCl, HNO2, HNO3, SO2, and NH3 was higher than that for ionic species, i.e., Cl-, NO3-, SO42- and NH4+ in fine particulates. For example, the removal efficiency was 185.7 +/- 7.8 and 66.2 +/- 22.3% for SO2 and NH3, respectively, whose inlet concentration ranged from 3.1 +/- 1.4 and 13.2 +/- 6.9 ppb, respectively. When gas pollutant concentration was at low level, it was observed that the concentration at the outlet was close to that at the inlet of the fine water spray device. This is due to the reduction of the concentration gradient at the gas-liquid interface, which lowers the absorption efficiency.