Determination of ammonia removal from aqueous solution and volumetric mass transfer coefficient by microwave-assisted air stripping

In this study, the removal of ammonia from synthetically prepared ammonia solution at pH 11 was investigated by using microwave radiation heating. Initially, conventional and microwave radiation heating were compared with respect to ammonia removal efficiency and overall volumetric mass transfer coefficient at five different temperatures. Overall volumetric mass transfer coefficient was calculated from the material balance for ammonia at unsteady-state condition. The effects of temperature, initial ammonia concentration, air flow rate, stirring speed, and microwave radiation power on both ammonia removal efficiency and overall volumetric mass transfer coefficient in liquid phase were also examined. The results of the experiments revealed that microwave-assisted air stripping allowed to the higher ammonia removal efficiency and overall volumetric mass transfer coefficient value compared to the conventional heating air stripping. Additionally, temperature and air flow rate were determined as the most substantial parameters affecting both ammonia removal efficiency and overall volumetric mass transfer coefficient value.