Decomposition of carboxymethyl cellulose based on nano-knife principle
Decomposition of carboxymethyl cellulose based on nano-knife principle
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基于纳米刀原理的羧甲基纤维素分解
DOI：
10.1016/j.jes.2018.10.007
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发表时间：
2019
影响因子：
6.9
通讯作者：
Pan Gang
中科院分区：
文献类型：
--
作者：
Zhou Qin;Hong Li;Di Bonito Marcello;Pan Gang
传统的有机污染物降解是基于牺牲化学或生物试剂。在这项研究中，开发了一种纯物理技术来打破化学键，从而分解水溶液中的大分子。在高速机械刀片的辅助下，具有特别锋利的纳米级边缘的精制石英砂颗粒可以充当“纳米刀”，能够切割羧甲基纤维素（CMC，作为模型分子）的长链。高效尺寸排阻色谱测量证明，原始CMC分子（41，000 Da）被分解成一系列更小的分子（460、1000、2200、21，000、27，000和31，000 Da）。因此，CMC溶液（2 g/L）的初始粘度在通过纳米刀材料沿着机械刀片处理3分钟后迅速降低约50%。傅里叶变换红外光谱（FTIR）表明，剪切后，原有的功能基团仍然存在，并没有产生新的功能基团。剪切后，观察到主要官能团β-1-4-糖苷键（波数1062 cm-1）的强度显著降低。这些结果表明，长链CMC被切割成短链CMC。提出了一种降解机制，即由纳米刀的快速运动产生的切割力可能是大分子纤维素主链中的β-1-4-糖苷键断裂的原因。这些结果提供了一个潜在的更经济实惠和环境友好的策略，从水溶液中的难降解有机污染物的物理为基础的分解，而不需要化学或生物试剂的支持。
The traditional degradation of organic pollutants is based on the sacrifice of chemical or biological reagents. In this study, a purely physical technique was developed to break the chemical bonds and consequently decompose macromolecules in aqueous solution. Assisted with a high-speed mechanical blade, refined quartz sand grains with particularly sharp nano-scale edges can act as ‘nano-knives’, which are able to cut the long chain of carboxymethyl cellulose (CMC, as a model molecule). High performance size exclusion chromatography measurements evidenced that the original CMC molecules (41,000 Da) were decomposed into a series of smaller molecules (460, 1000, 2200, 21,000, 27,000 and 31,000 Da). Consequently, the initial viscosity of the CMC solution (2 g/L) rapidly decreased by approximately 50% after 3 min treatment by the nano-knife materials along with the mechanical blade. Fourier transform infrared (FTIR) spectra indicated that the original functional groups were still present and new functional groups were not produced after shearing. The intensity of the main functional group β-1-4-glycosidic bond (wavenumber 1062 cm− 1) was observed to markedly decrease after shearing. These results indicated that the long-chain CMC was cleaved into short-chain CMC. A degradation mechanism was proposed whereby the cutting force generated by the rapid motion of the nano-knives may be responsible for the breakage of β-1-4-glycosidic bonds in the macromolecular cellulose backbone. These results provide support for a potentially more affordable and environment-friendly strategy for physical-based decomposition of recalcitrant organic pollutants from aqueous solution without the need of chemical or biological reagents.