Among the others, CO₂ and H₂S are the major impurities present in biogas which typically hampers its direct application as biofuel. Therefore, an upgradation for the purity of biogas is a high research endeavour. In the recent past, several attempts are made to improve the quality of biogas with a focus to reduce the impact of global warming due to the excessive release of CO₂. This is interesting to indicate that most of the biogas cleaning methods are expensive and very rare documents detailed the usage of sustainable materials for the purification of biogas. Given that, developments in the applications of natural materials as low-cost adsorbents used for the purification of biogas are well documented in the present review paper. Globally more than 40% of the countries utilise water scrubbing as the most popular method for the separation of biomethane. This article also reviews the other most accepted technologies such as different types of scrubbing, swing adsorption, and cryogenic separation with biological upgradation. Hybrid biological methods are used in methane upgrading systems to increase production of pure CH₄ while reducing the need for energy and chemicals. Moreover, the article also summarized different numerical models, frequently adopted for the prediction of the upgradation of biomass. Finally, the article concludes with major bottlenecks involved in the processes and recommended scientific directives towards successfully transforming bench-scale studies into large-scale implementation. So, this article will ensure the readers gather overall technical information on the upgradation of biogas obtained from the anaerobic digestion of biomass.

其中，CO ₂和H ₂ S是沼气中存在的主要杂质，这通常阻碍其作为生物燃料的直接应用。因此，提高沼气纯度是一项艰巨的研究工作。最近，人们进行了多项尝试来提高沼气的质量，重点是减少因过度释放 CO _{2而导致的全球变暖的影响}. 有趣的是，大多数沼气清洁方法都很昂贵，而且非常罕见的文件详细说明了可持续材料在沼气净化中的使用。鉴于此，本综述论文详细记录了天然材料作为用于净化沼气的低成本吸附剂的应用进展。全球超过 40% 的国家将水洗作为最流行的生物甲烷分离方法。本文还回顾了其他最被接受的技术，例如不同类型的洗涤、变吸附和生物升级的低温分离。混合生物方法用于甲烷升级系统以增加纯 CH _4的产量同时减少对能源和化学品的需求。此外，文章还总结了不同的数值模型，经常用于预测生物质的升级。最后，文章总结了过程中涉及的主要瓶颈，并推荐了科学指导，以成功地将实验室研究转化为大规模实施。因此，本文将确保读者收集有关生物质厌氧消化获得的沼气升级的整体技术信息。