College of Architecture and Environment, Sichuan University, Chengdu 610065, PR China.
SINOPEC Southwest Oil & Gas Company, Chengdu 610041, PR China.
Sci Total Environ. 2021 May 10;768:144452. doi: 10.1016/j.scitotenv.2020.144452. Epub 2021 Jan 6.
In this study, N-rich hierarchical porous carbons (NPCs) were synthesized via one step strategy from cypress sawdust with carbon nitride (CN) loading and KCO activation. NPCs exhibited excellent performance for HS removal with the sulfur capacity up to 426.2 mg/g at room temperature. It was much higher than 12.5 mg/g of porous carbon (PC) which was only activated by KCO. The NPCs with CN loading showed hierarchical porous structure with micropores and mesopores volume up to 0.434 and 0.597 cm/g, respectively. Moreover, NPCs had high N contents (up to 12.37 wt%) and high relative contents of pyridinic N and pyrrolic N within 76.61-84.37%, which were identified as active sites for HS adsorption by density functional theory calculation, enhancing HS removal. The formation mechanism of NPCs was investigated by TG-FTIR, suggesting that CN pyrolysis result in hierarchical porous structure and rich N-containing functional groups by gradually releasing HO, CO and NH. Moreover, the NPCs showed high regeneration ability, remaining 86.6% of the initial sulfur capacity after five regeneration cycles, and sulfur (S) was the main desulfurization product (HS + O → S + HO). The results demonstrate that NPCs are promising catalysts to remove HS efficiently with low cost and high reusability.
在这项研究中，通过将氮化碳（CN）负载和 KCO 活化一步法从柏木锯末合成了富氮分级多孔碳（NPCs）。NPCs 对 HS 的去除表现出优异的性能，在室温下的硫容量高达 426.2 mg/g，远高于仅用 KCO 活化的多孔碳（PC）的 12.5 mg/g。负载 CN 的 NPCs 具有分级多孔结构，微孔和介孔体积分别高达 0.434 和 0.597 cm/g。此外，NPCs 具有高 N 含量（高达 12.37 wt%）和高吡啶 N 和吡咯 N 的相对含量（76.61-84.37%），通过密度泛函理论计算，鉴定其为 HS 吸附的活性位，增强了 HS 的去除。通过 TG-FTIR 研究了 NPCs 的形成机制，表明 CN 热解通过逐渐释放 HO、CO 和 NH 导致分级多孔结构和富含含 N 官能团的形成。此外，NPCs 表现出高的再生能力，经过五次再生循环后仍保持初始硫容量的 86.6%，主要脱硫产物为 S（HS + O → S + HO）。结果表明，NPCs 是一种很有前途的高效、低成本、高可重复使用的 HS 去除催化剂。
