Synthesis of natural zeolite adsorbent for CO₂ adsorption

Zeolite is one of the adsorbent materials that reduce CO₂ in biogas, due to being a mineral with silica-alumina clusters, which cross-knits through the binding of oxygen atoms to the hydrated structure (Al-Si)O₄ of alkali metals and alkaline soils. Natural zeolites generally have less crystallinity, different pore size, and many metal oxides. Therefore, this study aims to improve the quality of natural zeolite through activation and modification. Using FTIR spectroscopy, the activation of this mineral utilized NaOH and calcination at 500°C, where the analysis of specific chemical bonds and functional groups indicated a reduction in silica and the ratio of Si /Al. This activation technique also caused a greater adsorption capacity value by using bases (NaOH), with the zeolite structure becoming more negative. Subequently, activation did not form new compounds, as it only removed impurities for pore optimization. The ZA1M activation decreased and increased the CO₂ and CH₄ concentrations of the biogas. The percentages of CO₂ removal used ZA, ZA1M, and ZA5M were 14,90%, 25,48% and 46,95% using flowrate of biogas 2000 ml/min for 15 min and 50 cm high of zeolite packing