Adsorption Contact Time Effect of Carbon Dioxide Adsorption Using Rice-Straw Biochar on Biogas Performance

Biogas purification should be done to enrich methane composition in biogas. The technology to enrich methane composition is by removing carbon dioxide as impurity gas. The effect of carbon dioxide adsorption in biogas has been investigated. In this study, biogas purification using rice-straw biochar aimed to reduce carbon dioxide composition in biogas increasing biogas performance. The experiment used different adsorption times. The treatment contact time of adsorption was divided into four treatments: 10, 15, 20, and 25 min. Before the experiment, the optimal volume of adsorbent also has been investigated. The result showed that the use of 100% by volume of biochar is the most optimal volume of adsorbent. The result also showed a decrease in carbon dioxide composition from four treatments in the different adsorption contact times by 75.57; 8.2; 3.11; and – 13.81%, respectively. The highest carbon dioxide adsorption was performed by 10 min of adsorption time. With the increasing adsorption time, the carbon dioxide adsorption ability also decreased. In the 20 min of adsorption time, the rice-straw biochar showed a saturation point, so the optimal adsorption time is 20 min.