Original Article | 2012, Vol.34, No.4, pp. 423-432
Modeling and optimization of ammonia treatment by acidic biochar using response surface methodology
Narong Chaisongkroh, Juntima Chungsiriporn and Charun Bunyakan
pp. 423 - 432
Abstract
Emission of ammonia (NH3 ) contaminated waste air to the atmosphere without treatment has affected humans and environment. Eliminating NH3 in waste air emitted from industries is considered an environmental requisite. In this study, optimization of NH3 adsorption time using acidic rubber wood biochar (RWBs) impregnated with sulfuric acid (H2SO4) was investigated. The central composite design (CCD) in response surface methodology (RSM) by the Design Expert software was used for designing the experiments as well as the full response surface estimation. The RSM was used to evaluate the effect of adsorption parameters in continuous mode of fixed bed column including waste air flow rate, inlet NH3 concentration in waste air stream, and H2 SO4 concentration for adsorbent surface modification. Based on statistical analysis, the NH3 symmetric adsorption time (at 50% NH3 removal efficiency) model proved to be very highly significant (p<0.0001). The optimum conditions obtained were 300 ppmv inlet NH3 concentration, 72% H2 SO4, and 2.1 l/min waste air flow rate. This resulted in 219 minutes of NH3 adsorption time as obtained from the predicted model, which fitted well with the laboratory verification result. This was supported by the high value of coefficient of determination (R2 =0.9137). (NH4)2SO4 , a nitrogen fertilizer for planting, was the by-product from chemical adsorption between NH3 and H2 SO4.
