Advanced modification of natural zeolites for optimized biogas, syngas, and hydrogen production and purification

Abstract

The industrial production of biogas, syngas, and hydrogen often relies on costly synthetic adsorbents and catalysts. However, natural zeolites (NZs) offer a cost-effective alternative, potentially enhancing reaction speeds as adsorbents, membranes, and catalysts. Despite their availability, the utilization of NZs and modified NZs in gas production and purification is underreported. This study aims to systematically review recent advancements in NZ modification techniques to optimize their role in generating, purifying, and enhancing biogas, syngas, and hydrogen. Bibliometric techniques were employed to analyze various NZ properties, including Si/Al ratio, surface area, microporosity, morphology, crystallinity, ion exchange capacity, and stability. Five primary modification methods—ion exchange, acid-base treatment, surface treatment, surfactant treatment, and plasma-assisted treatment—were assessed for their effects on improving gas production and purity. Key findings suggest that acid treatment, calcination, ion exchange impregnation, and coating can enhance critical factors such as Si/Al ratio and ion exchange capacity. However, achieving high selectivity across multiple gas combinations remains challenging due to the variable composition of biogas and syngas. Moreover, the sustainability and cost-effectiveness of NZ activation methods, along with the commercial viability of using modified NZs, require further investigation. This study offers valuable insights into NZ potential, guiding future research toward more efficient and sustainable energy production.

Keywords

• Natural zeolite
• biogas
• syngas
• methane
• hydrogen
• modification