Immobilization of nanosilver onto glycine modified lignin hydrogel composites for highly efficient p-nitrophenol hydrogenation
Immobilization of nanosilver onto glycine modified lignin hydrogel composites for highly efficient p-nitrophenol hydrogenation
复制标题
将纳米银固定在甘氨酸改性木质素水凝胶复合材料上用于高效对硝基苯酚氢化
DOI：
10.1016/j.cej.2020.126370
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发表时间：
2021-01-01
影响因子：
15.1
通讯作者：
An, Qingda
中科院分区：
文献类型：
--
作者：
Gao, Ce;Xiao, LingPing;An, Qingda
采用甘氨酸修饰木质素水凝胶制备了一种新型纳米银固定化催化剂，对硝基苯酚还原具有优异的催化性能。甘氨酸为银离子络合提供氨基和羧基，同时也有利于银纳米粒子的原位还原和抑制。采用x射线衍射、EDS扫描电镜、高分辨率透射电镜、x射线光电子能谱、傅里叶变换红外光谱仪和热重分析仪对制备的复合材料进行了表征。发达的网络和丰富的锚定位点可以在催化过程中提供稳定性和足够的牵引力来分散和稳定纳米银颗粒。进行了4-NP加氢的批量实验，以考察其催化性能。浓度为5 mmol/L的4-NP仅需101 s， k速率为0.0151 s（-1）。并创造性地采用固定床实验进行试验，在3 mL/min的流速下，催化剂能保持300 min左右的高效率。重复使用10次后，催化剂的转化率保持在98%以上；纳米银的浸出忽略了纳米银的浸出，这可能是由于引入的甘氨酸组分起着至关重要的作用。
A new type of nanosilver immobilized catalyst based on glycine modified lignin hydrogels with excellent catalytic performance towards p-nitrophenol reduction have been prepared. Glycine was used to provide amino and carboxy groups for complexing silver ions, simultaneously which was also beneficial for in-situ reduction and suppression of silver nanoparticles. As-prepared composites were characterized by X-ray diffraction, scanning electron microscope with EDS, high-resolution transmission electron microscope, X-ray photoelectron spectroscopy, Fourier Transform Infrared Spectrometer and Thermal Gravimetric Analyzer. The developed network with enriched anchoring sites could provide the stability during the catalytic process and enough traction to disperse and stabilize the silver nanoparticles. Batch experiments of 4-NP hydrogenation were carried out to correlate the catalytic performance. The concentration of 4-NP of 5 mmol/L could be finished with only 101 s and the rate of k was 0.0151 s(-1). Moreover, fixed-bed experiments were creatively applied for the tests and the catalyst can maintain high efficiency about 300 min with the flowing rate of 3 mL/min. After being reused ten cycles, the catalyst retained the conversion rate beyond 98%; and the structure has no obvious deterioration and the leaching of nanosilver was neglectful, which could be attributed to the crucial role of introduced glycine component.