Preparation of bacterial cellulose membranes from nata De coco with and without silver ions for CO2/CH4 separation

Abstract

Carbon dioxide removal from natural gas is an important process because the existence of carbon dioxide in natural gas contributes to pipeline corrosion, reduces the heating value, and takes up volume in the pipeline. In this study, bacterial cellulose was chosen for the gas separation membrane due to the unique structure and prominent properties of bacterial cellulose. Moreover, bacterial cellulose can be obtained simply by culturing the bacteria so called “Acetobacter xylinum” through fermentation of coconut juice which is available abundantly in Thailand. Bacterial cellulose membranes with and without silver ions were prepared to investigate the effect of silver ions on the CO2/CH4 separation performance. Bacterial cellulose membranes without silver ions were prepared by varying the weight ratios of dried Nata de coco to water. SEM micrographs and gas pycnometer measurements were shown the effect of the addition of water. The gas separation measurements showed that bacterial cellulose membrane with the weight ratio of 1:10 achieved the highest CH4/CO2 selectivity and thus it was chosen for further studying the gas separation performance by impregnating with AgNO3 solutions. The 1.0M Ag+-BC membrane showed the highest CH4/CO2 selectivity. The increasing of AgNO3 concentrations could improve the selectivity.