Nitro-oxidized carboxycellulose nanofibers from moringa plant: effective bioadsorbent for mercury removal
Nitro-oxidized carboxycellulose nanofibers from moringa plant: effective bioadsorbent for mercury removal
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DOI：
10.1007/s10570-021-04057-5
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发表时间：
2021-07-14
期刊：
影响因子：
5.7
通讯作者：
Hsiao, Benjamin S.
中科院分区：
文献类型：
--
作者：
Chen, Hui;Sharma, Sunil K.;Hsiao, Benjamin S.
饮用水中的汞污染是一个世界性的问题，因为它对人体有严重的危害。利用硝基氧化法从辣木原料中提取的纳米结构天然生物吸附剂羧纤维素纳米纤维（NOCNF）能够有效地解决这一问题。硝基氧化是一种简单的方法，可以直接从原料生物质中提取羧化纳米纤维素。在本研究中，生产的NOCNF在纤维素表面含有大密度的羧酸基团（0.97 mmol/g），能够同时通过静电相互作用和矿化过程去除Hg2+离子。Langmuir分析结果表明，NOCNF对Hg2+的最高去除率为257.07 mg/g，高于大多数报道的值。利用傅里叶变换红外光谱、扫描电镜/能谱（SEM/EDS）、透射电镜电子衍射和广角x射线衍射等方法对Hg2+与NOCNF的相互作用进行了进一步表征，表明存在两种不同的去除机制：低Hg（2+）浓度（< 250 ppm）下的主要吸附机制和高Hg2+浓度（> 1000 ppm）下的主要矿化机制。说明了NOCNF在悬浮液（作为吸附剂/混凝剂）和干粉（通过过滤柱）两种形式下的应用。结果表明，悬浮状态下NOCNF的最大去除率为81.6%，高于干燥状态下的74.3%。这项工作证明了从生物质原料中提取纳米结构吸附剂来解决饮用水中Hg2+污染问题的可行性。
Mercury contamination in drinking water is a worldwide problem due to its severely harming effects on the human body. A nanostructured natural bioadsorbent, carboxycellulose nanofiber extracted from raw moringa plant using the nitro-oxidation method (termed NOCNF), capable of effectively remediating this problem has been demonstrated. Nitro-oxidation is a simple approach that can extract carboxylated nanocellulose directly from raw biomass. In this study, the produced NOCNF contained a large density of carboxylate groups on the cellulose surface (0.97 mmol/g), capable of removing Hg2+ ions by simultaneous electrostatic-interactions and mineralization processes. Using the Langmuir analysis, the adsorption results indicated that the highest Hg2+ removal capacity of this NOCNF was 257.07 mg/g, which is higher than most of the reported values. The interactions between Hg2+ and NOCNF were further characterized by Fourier-transform infrared spectroscopy, scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS), transmission electron microscopy with electron diffraction and wide-angle X-ray diffraction methods, suggesting the existence of two distinct removal mechanisms: predominant adsorption at low Hg(2+ )concentrations (< 250 ppm) and predominant mineralization at high Hg2+ concentrations (> 1000 ppm). The applications of NOCNF were illustrated in both suspension form, as an adsorbent/coagulant, and dry powder form using filtration column. The results indicated that NOCNF in suspension exhibited a higher maximum removal efficiency of 81.6% as compared to the dry state of 74.3%. This work demonstrated the feasibility of extracting nanostructured adsorbents from biomass feedstocks to tackle the Hg2+ contamination problem in drinking water.[GRAPHICS].