Carbon Dioxide Adsorption on Chicken Manure or Biogas Sludge derived Biochar and its modification to enrich Methane Composition in Biogas

Although biogas has multiple benefits, biogas implementation might fail in many developing countries. There are many challenges in its implementation and one of them is lower calorific value. The reduction of carbon dioxide enhances the calorific value. The objective of this study was to investigate the effect of carbon dioxide adsorption using natural zeolite (Z-Z), the combination of natural zeolite and chicken manure based biochar (Z-B1), the combination of natural zeolite and biogas sludge based biochar (Z-B2), the combination of natural zeolite and modified chicken manure based biochar (Z-B1N) and the combination of natural zeolite and modified biogas sludge based biochar (Z-B2N) on methane composition in biogas. Modified biochar was carried out by immersion in ammonia solution. The adsorption of carbon dioxide was carried out at room temperature and gas pressure ranged between 5-7 bar. The adsorbents were characterized with infrared (IR) spectroscopy, surface area analyzer (SAA) and scanning electron microscopy (SEM). Methane composition increased after adsorption and the highest methane enrichment was performed by Z-B1 (28.92%) followed by Z-B2 (5.12%). Unfortunately, surface modification on biochar could not improve its capability in carbon dioxide adsorption. Carbon dioxide adsorption on Z-B1N and Z-B2N enhanced methane level by 11.27% and 3.43% respectively. Therefore, chicken manure and biogas sludge based biochars can be used as alternative carbon dioxide adsorbent in biogaspurification.