Abstract:

Hydrogen, as a carbon-neutral energy carrier with diverse production pathways and application scenarios, requires efficient purification from industrial by-product gas streams containing CO, CO₂, CH₄ and N₂ impurities. Particularly, CO removal is critical to meet the <5μL/L purity standard for hydrogen fuel cells. Among purification technologies, adsorption separation stands out for its cost-effectiveness and scalability. This study developed copper-modified activated carbon adsorbents through an innovative "load-first-then-reduce" impregnation method using CuCl₂‧2H₂O precursors. The CO adsorption performance was systematically evaluated through a custom-built gas separation system complemented by comprehensive characterization via BET surface area analysis, XRD crystallography and UV-vis spectroscopy. The gas adsorption isotherms (CO, CO₂, CH₄, N₂, H₂) of the modified activated carbon at 300K all met the Langmuir (R²=0.99) and Freundlich (R²=0.999) models. The adsorption capacities for the five gases were as follows: CO 20.06cm³/g and CO₂ 41.12cm³/g, which were much higher than those for CH₄ 14.20cm³/g, N₂ 3.86cm³/g and H₂ 0.57cm³/g. Modified activated carbon (AC) had significantly increased CO adsorption compared to the original AC, and was extremely selective to other gases (CO, CO₂, CH₄, N₂) and hydrogen. Cyclic adsorption-desorption tests confirmed >86% capacity retention after 10 cycles, indicating superior reversibility for industrial applications. This work provided a viable strategy for tailoring adsorbents to specific hydrogen-rich feed gas compositions, bridging the gap between low-cost purification and fuel cell-grade hydrogen production.

Key words: activated carbon, adsorbent, selectivity, carbon monoxide, hydrogen purification

摘要：

为了对富氢原料气中的氢气进行提纯，需要分离其中的CO、CO₂、CH₄、N₂等杂质气体，同时为了配合氢燃料电池的用氢标准，还需要提高对关键性杂质CO的分离能力。本文以商用活性炭和二水合氯化铜为原料，以“先负载、后还原”的思路，采用浸渍法制备了负载亚铜离子的改性活性炭。通过自建的反应系统对制备的改性活性炭进行CO吸附性能测试并结合物理吸附、X射线衍射、紫外-可见-近红外分光光度测试等表征，探究了改性条件、浸渍条件对活性炭结构以及吸附性能的影响。结果表明，在300K温度下CO、CO₂、CH₄、N₂和H₂气体在该吸附剂上的吸附平衡等温线可以很好地用Langmuir和Freundlich模型拟合。改性活性炭对CO的吸附量为20.06cm³/g，对CO₂的吸附量为41.12cm³/g，远高于对CH₄（14.20cm³/g）、N₂（3.86cm³/g）和H₂（0.57cm³/g）的吸附量。常温条件下，改性后的载铜活性炭的CO吸附性能得到了显著提高，并具有很高的CO/H₂、CO/CO₂、CO/CH₄和CO/N₂吸附选择性和良好的可逆性。

关键词: 活性炭, 吸附剂, 选择性, 一氧化碳, 氢气纯化