Altaf Adnan Raza, Teng Haipeng, Gang Liu, Adewuyi Yusuf G, Zheng Maosheng
School of Chemical Engineering, Northwest University, Xi'an 710069, China.
State Key Laboratory of Clean Coal-based Energy, China Huaneng Group Clean Energy Research Institute Co., Ltd., Changping District, Beijing 102209, China.
ACS Omega. 2021 Sep 8;6(37):23913-23923. doi: 10.1021/acsomega.1c02925. eCollection 2021 Sep 21.
Elemental mercury (Hg) removal from a hot gas is still challenging since high temperature influences the Hg removal and regenerable performance of the sorbent. In this work, a facile yet innovative sonochemical method was developed to synthesize a thermally stable magnetic tea biochar to capture the Hg from syngas. A sonochemically synthesized magnetic sorbent (TUF) exhibited a more prodigious surface area with developed pore structures, ultra-paramagnetic properties, and high dispersion of FeO/γ-FeO particles than a simply synthesized magnetic sorbent (TF). The results showed that TUF demonstrated strong thermostability and attained a high Hg removal performance (∼98.6%) at 200 °C. After the 10th adsorption/regeneration cycle, the Hg removal efficiency of TUF was 19% higher than that of TF. Besides, at 23.1% Hg breakthrough, TUF achieved an average Hg adsorption capacity of 16.58 mg/g within 24 h under complex syngas (20% CO, 20% H, 5% HO, and 400 ppm HS). In addition, XPS results revealed that surface-active components (Fe, O, O*, C=O) were the key factor for high Hg removal performance over TUF from syngas. Hence, sonochemistry is a promising practical tool for improving the surface morphology, thermal resistance, renewability, and Hg removal efficiency of a sorbent.
从热气体中去除元素汞（Hg）仍然具有挑战性，因为高温会影响吸附剂的汞去除和可再生性能。在这项工作中，开发了一种简便而创新的声化学方法，以合成一种热稳定的磁性茶生物炭，用于从合成气中捕获汞。与简单合成的磁性吸附剂（TF）相比，声化学合成的磁性吸附剂（TUF）表现出更大的表面积、发达的孔隙结构、超顺磁性以及FeO/γ-FeO颗粒的高分散性。结果表明，TUF表现出很强的热稳定性，在200°C时具有较高的汞去除性能（约98.6%）。在第10次吸附/再生循环后，TUF的汞去除效率比TF高19%。此外，在汞穿透率为23.1%时，TUF在复杂合成气（20%CO、20%H、5%H₂O和400 ppm H₂S）下24小时内的平均汞吸附容量达到16.58 mg/g。此外，X射线光电子能谱（XPS）结果表明，表面活性成分（Fe、O、O*、C=O）是TUF对合成气中汞具有高去除性能的关键因素。因此，声化学是一种很有前景的实用工具，可用于改善吸附剂的表面形态、耐热性、可再生性和汞去除效率。
