Biogas has become widely used renewable energy source. However, the methane content only ranges between 40 - 75%. The innovation uses the abundantly available natural zeolite, as solid absorbent to purify biogas, to reduce corrosion potential to stoves or other energy conversion engine that uses the biogas. The test prove that the methane content of biogas can be increase up to 20%, and the filter can function effectively at a low gas pressure (~ 0 bar) at ambient temperature.