The present PPWS provides a large specific surface area to
increase the contact between liquid film and gas pollutants. The
gap between the plates can be adjusted easily to control the gas
retention time and the gas flow rate can be increased further by
increasing the size and the number of the MPPM. It is expected that
the present PPWS can be scaled up as an efficient control device
with a very low pressure drop for the treatment of low-concentration
soluble acid and basic gases. In the future, the removal efficiency
of the PPWS for basic gas and soluble VOCs is worth
further investigation. In addition, the validation of the effect of acid
gas temperature on the removal efficiency at room temperature
will be also explored. Further study on the long-term field test
for both high and low inlet concentrations is also necessary.