Liquid-solid phase countercurrent multi-stage adsorption process for using the Langmuir equation

Mass balance and the Langmuir equation were used to deduct the countercurrent multi-stage adsorption process. The relationships between the Langmuir parameter (KLyi) and the required amounts of adsorbent in countercurrent two-, three- and infinite-stage processes were obtained to find the optimum number of stages as well as the reduction in the adsorbent consumption of the countercurrent multi-stage process of an adsorption system. Pistachio shell activated carbons with BET surface areas of 1013, 1398, and 1919 m2/g were obtained by KOH activation with CO2 gasification at gasification times of 0, 10, and 30 min. The isotherm adsorption of four adsorbates were investigated and analyzed with the Langmuir equation. The activated carbons studied in this work show compared with other published literatures, the KLyi and qmon values in this work showed excellent adsorption performance. The amount of activated carbon for a countercurrent two- and single stage adsorption operation was calculated, a saving of 66-87% adsorbent was obtained. A simple countercurrent two-stage adsorption system was designed for use in engineering applications.