Discovering the Interference of Hydrogen Sulfide on Polyethylenimine-Functionalized Porous Resin for Biogas Upgrading via CO₂ Adsorption

Abstract

Because of the considerable CO2 adsorption capacity, selectivity, and stability, amine-functionalized materials have been recently investigated as promising adsorbents for biogas upgrading to biomethane, which provides the preferred gaseous bioenergy resource. Nevertheless, the typical impurity in biogas, H2S, has a potential influence on biogas upgrading, as another acid component to react with amines besides CO2. After all, even the trace H2S after biogas desulfurization might have an accumulative effect, based on previous experience in studying other acid impurities. Herein, we explored the interference of H2S (5–5000 ppm) on the prepared polyethylenimine-functionalized porous resin (PEI/HP20), which has exhibited excellent performance for biogas upgrading. The distinct of adsorption capacity, kinetic behavior, and regeneration performance between the two reactive components (CO2 and H2S) in biogas was systemically investigated. It was found that, in contrast with CO2, the adsorbed H2S on PEI/HP20 was not comparable through slow single-stage kinetic behavior and had limited impact, especially in consideration of the practical biogas upgrading within finite time. Besides, the reversible binding of H2S, proved by the regeneration performance and chemical characterization, was also favorable and pivotal for the PEI/HP20. In addition, the stable operation (capacity loss of 1%) by continuous adsorption–regeneration cycles under H2S-containing simulated biogas have finally demonstrated the ignorable interference of H2S on PEI/HP20, manifesting its strong adaptability in biogas upgrading.

Design and Optimization of Solid Amine CO2 Adsorbents Assisted by Machine Learning

“…It is worth noting that unlike CO 2 adsorption capacity and amine efficiency, amine type is the most critical factor affecting the stability of the adsorbent, and the pore volume, pore size, and specific surface area have little effect on the stability of the adsorbent (Figure e). It is because PEI has a larger molecular weight than TEPA, and the larger the molecular weight of the organic amine, the better its stability, which is consistent with the reports in the literature. ,,, For the adsorption rate and τ 90 of the adsorbents, the ranking of each feature importance score is the same as that of the adsorption amount, in which the amine loading, pore volume, and pore size were identified as the main factors affecting the performance, as shown in Figure S2.…”

“…It is because PEI has a larger molecular weight than TEPA, and the larger the molecular weight of the organic amine, the better its stability, which is consistent with the reports in the literature. 14,27,40,41 For the adsorption rate and τ 90 of the adsorbents, the ranking of each feature importance score is the same as that of the adsorption amount, in which the amine loading, pore volume, and pore size were identified as the main factors affecting the performance, as shown in Figure S2.…”

“…On the other hand, the pore structure of the support is another important influence on the adsorption performance of the solid amine adsorbent. The most explored supports are silicon materials with different structures (i.e., SBA-15, − MCM-41, porous silica gel , ), varieties of activated carbon materials, − MOFs, , porous polystyrene-type resins, , and other porous materials. − In recent years, many researchers have devoted themselves to the preparation of complex macro-/mesoporous materials, which are beneficial to increase the loading of amines and increase the adsorption sites to increase the CO 2 adsorption capacity. Lou et al prepared macro-/mesoporous silica nanospheres with an inverted-conical pore structure, which exhibited the maximum CO 2 adsorption capacity (4.09 mmol/g) at 65 wt % PEI loading.…”

Efficient and stable CO2 capture using a scalable and spontaneous cross-linking amine-functionalized nano-Al2O3 adsorbent

“…3D). [36][37][38][39][40][41][42][43][44][45][46] 60%PEI@Al 2 O 3 exhibited an excellent CO 2 uptake and amine efficiency owing to the large pore volume and unique pore structure of interwoven tentacles on nano-Al 2 O 3 . Despite not exhibiting the highest CO 2 uptake or amine efficiency, 60% PEI@Al 2 O 3 still holds promise owing to its dual advantages in CO 2 uptake and amine efficiency, irrespective of the CO 2 concentration during the adsorption process.…”

Hyper-Crosslinked Resins Modified by Ferrocene for CO2/CO and CO2/CH4 Separation

“…In addition, St-DVB-HCPs have exhibited more advantages, such as excellent stability, flexible function, and a simple synthetic process. Most of the St-DVB-HCPs have been widely applied in the field of water purification and ion collection, while only a few resins modified by amines have been used for CO 2 capture. , Although different kinds of amines can increase the CO 2 adsorption capacity and improve the selectivity, the value of adsorption enthalpy is also increased, leading to an energy-intensive regeneration process. Therefore, it is time to replace the CO 2 adsorption method relying on an acid–alkaline effect.…”