Study of various diameter and functionality of TEMPO-oxidized cellulose nanofibers on paraquat adsorptions
Study of various diameter and functionality of TEMPO-oxidized cellulose nanofibers on paraquat adsorptions
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DOI：
10.1016/j.polymdegradstab.2019.01.023
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发表时间：
2019-03-01
影响因子：
5.9
通讯作者：
Lin, Kun-Yi Andrew
中科院分区：
文献类型：
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作者：
Huang, Chih-Feng;Tu, Cheng-Wei;Lin, Kun-Yi Andrew
研究了2，2，6，6-四甲基哌啶1-氧（克里思）氧化纤维素纳米纤维（TOCN）在不同氧化时间（TOCN-1h、TOCN-4 h、TOCN-8h和TOCN-24 h）下对百草枯的吸附。首先，我们监测TEMPO介导的氧化时间，纤维素表面官能团，和纤维直径之间的关系。我们观察到纤维素的氧化和羧酸盐含量在一小时内迅速增加，导致纳米尺寸的纤维素纤维（约100 μ m）的形成。20 nm）。采用傅里叶变换红外光谱（FT-IR）、扫描电子显微镜（SEM）、BET法和广角X射线衍射（WAXRD）对纤维素纳米纤维进行了表征。因此，具有增大的比表面积（约. 180 m（2）/g）对百草枯的吸附效率较高（>90%），这是由于TOCN上的羧酸根阴离子与parquet阳离子之间存在较强的吸引力。吸附行为采用颗粒内扩散（IPD）模型。对于TOCN-24 h，观察到吸附质从表面到半纤维素或无序区域内的活性位点的IPD，导致吸附平衡时间增加。在不同pH环境下，吸附性能较为敏感。在pH值大于或等于7时，吸附容量可达到100 mg/g以上。不同温度下的吸附行为均符合Langmuir吸附等温式，表明吸附机理为单层吸附。(C)2019爱思唯尔有限公司版权所有。
The adsorption of paraquat was examined in the presence of renewable nanomaterials of 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) oxidized cellulose nanofibers (TOCNs) with different oxidation time (i.e. TOCN-1h, TOCN-4h, TOCN-8h, and TOCN-24h). First, we monitored the relationships among TEMPO-mediated oxidation times, cellulose surface functional groups, and fiber diameters. We observed the oxidation and the carboxylate contents of cellulose were promptly increased in an hour, leading to the formation of nano-sized cellulose fibers (ca. 20 nm). These cellulose nanofibers were characterized by Fourier-transform infrared (FT-IR), scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) method, and wide angle X-ray diffraction (WAXRD). Accordingly, the TOCNs with enlarged specific surface area (ca. 180 m(2)/g) performed high adsorption efficiency for paraquat (>90%), contributing from the strong attraction force between carboxylate anion on TOCNs and parquet cation. The adsorption behaviors were revealed by intra-particle diffusion (IPD) model. For TOCN-24 h, IPD of adsorbate from the surface to the active sites within the hemicellulose or disorder region was observed, resulting in the increase of the adsorption equilibrium time. We then comprehended the absorption performance was sensitive under different pH environments. The adsorption capacity over 100 mg/g can be reached at a pH value greater or equal to 7. Furthermore, Langmuir isotherm model was fitted to the adsorption behaviors at various temperatures, indicating a single layer adsorption mechanism. (C) 2019 Elsevier Ltd. All rights reserved.