The Substitution of Natural Zeolite with Agriculture Waste as Carbon Dioxide Adsorbent in Biogas Purification

Abstract Today, climate change is a global issue that must be resolved as soon as possible. Many governments take action to include renewable energy in energy mix policy. For Indonesia, biogas energy becomes one of many adopted alternative renewable energy sources. To increase the adoption of biogas in energy mix of Indonesia, biogas improvement should be enhanced. Biogas purification by adsorption is one of many methods of biogas improvement. To reduce the cost of biogas purification, we substitute natural zeolite with a local and waste-based adsorbent, the rice husk-based-biochar. In this study, we used five formulations with different ratios of zeolite and biochar: A1 (100% of natural zeolite), A2 (75%:25%), A3 (50%:50%), A4 (25%:75%), and A5 (100% of biochar) to decrease carbon dioxide composition and increase the calorific value of biogas. The substitution of 25% volume of zeolite with rice husk-based-biochar adsorbed 10.63% carbon dioxide. However, the substitution above 25% actually reduced the ability to adsorb carbon dioxide. The results showed that there is no correlation between carbon dioxide and the calorific value of biogas so further study needs to be developed to improve the biogas purification.