Separation of Dissolved Gases from Aqueous Anaerobic Effluents Using Gas-Liquid Membrane Contactors

This study aimed to evaluate a gas-liquid membrane contactor for recovering the dissolved gases of methane (CH4) and carbon dioxide (CO2) from model aqueous anaerobic effluents. For this purpose, synthetic effluents were prepared by using the gas mixtures of SE-1: 100/0, SE-2: 0/100 and SE-3: 50/50 CH4/CO2 vol.% as well as DI water. The units in which the synthetic effluent was prepared were coupled with a dense hollow fiber membrane module by employing argon gas at atmospheric pressure. The desorption of the gases CH4 and CO2 dissolved in the effluents was investigated with a countercurrent flow of the liquid on the lumen side. The effect of the sweep gas flow rate on the removal rate was also investigated. The results showed that the recovery rate of CH4 was slightly affected by increasing the sweep gas flow rate, while the recovery rate of CO2 was enhanced considerably. By applying a sweep gas flow rate of 20 mL/min, the recovery rate of both gases from SE-3 exceeded 50%.