The separation of CO₂ from biogas to achieve vehicle/pipeline grade methane is an expensive step. Recently, PEI (polyethyleneimine) impregnated resins have been proposed and evaluated for CO₂ separation from flue gases and air. However, its use in biogas upgrading and evaluation of the economic feasibility of such adsorbents have not been explored in detail. In this work, by modifying an inert polymeric resin (HP2MGL) using PEI, CO₂ was separated from biogas. The sorbent exhibited the highest adsorption capacity of 2.7 mmol_CO2/g_ads at 30% PEI loading, increasing to 2.9 mmol_CO2/g_ads in the presence of moisture, and remained stable for up to five adsorption–desorption cycles. In situ DRIFTS studies showed that CO₂ adsorption on PEI-impregnated sorbent is consistent with the zwitterion reaction mechanism, and the sorbent could be regenerated completely at 100 °C. The upgrading cost of biogas is primarily dominated by the operating cost of regeneration and the adsorbent cost. The economic feasibility analysis suggests that PEI-impregnated resin sorbent requires less capital and operating costs than conventional biogas upgrading technologies. Therefore, PEI-impregnated polymeric resins are promising for CO₂ separation from biogas.

从沼气中分离 CO ₂以获得车辆/管道级甲烷是一个昂贵的步骤。最近，PEI（聚乙烯亚胺）浸渍树脂已被提出并评估用于从烟道气和空气中分离CO ₂。然而，其在沼气提纯中的应用和此类吸附剂的经济可行性评价尚未得到详细探讨。在这项工作中，通过使用 PEI 改性惰性聚合物树脂 (HP2MGL)，从沼气中分离CO ₂。吸附剂在 30% PEI 负载下表现出最高的吸附容量 2.7 mmol _CO2 /g _ads，增加到 2.9 mmol _CO2 /g _ads在水分存在的情况下，并在多达五个吸附-解吸循环中保持稳定。原位 DRIFTS 研究表明，PEI 浸渍的吸附剂对CO _{2 的}吸附符合两性离子反应机理，吸附剂可以在 100 °C 下完全再生。沼气升级成本主要由再生运行成本和吸附剂成本决定。经济可行性分析表明，与传统沼气升级技术相比，PEI 浸渍树脂吸附剂所需的资金和运营成本更少。因此，PEI 浸渍的聚合物树脂有望用于从沼气中分离CO ₂。