Fabrication of aerogels from cellulose nanofibril grafted with β-cyclodextrin for capture of water pollutants
Fabrication of aerogels from cellulose nanofibril grafted with β-cyclodextrin for capture of water pollutants
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DOI：
10.1007/s10934-021-01109-w
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发表时间：
2021-07-02
影响因子：
2.6
通讯作者：
Peresin, Maria Soledad
中科院分区：
文献类型：
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作者：
Gomez-Maldonado, Diego;Reynolds, Autumn Marie;Peresin, Maria Soledad
分子和表面化学的相互作用是决定多孔材料中污染物和新兴污染物吸附能力的一些关键因素。随着基于过滤的水源净化的扩展，生物聚合物等绿色材料的产生成为首要任务。然而，为了提高去除能力，天然聚合物的改性似乎是必要的。纳米材料，特别是生物基材料，如纤维素纳米纤丝，由于其高纵横比而固有地具有大的表面积。它们调节与存在于水中的污染物的相互作用的能力可以通过引入选择性活性点（例如疏水空腔）来调节，这可以进一步提高它们的总体吸附能力。可以满足这一要求的生物基材料是β-环糊精，一种具有七个葡萄糖单元的环状寡糖，由于结构亲和力，它提供了一种简单的接枝到纤维素上的策略。使用纤维素纳米原纤维的另一个优点是它们的成膜性、气凝胶和水凝胶，而不需要苛刻的化学品或工艺。在这项工作中，具有疏水中心的寡糖-β-环糊精-被固定到漂白的软木纤维素纳米纤丝上，然后用于产生密度为175 kg/m3且孔隙率高于88%的高表面积气凝胶。电荷密度滴定，傅里叶变换红外衰减全反射（FTIR-ATR），X射线光电子能谱（XPS），热重分析（TGA），和原子力显微镜（AFM）表征技术被用来评估成功的改性的原纤。电感耦合等离子体质谱（ICP-MS）用于确定缺乏微量氯的接枝过程中的材料，而扫描电子显微镜（SEM）和动态蒸汽吸附（DVS）用于确定气凝胶的孔隙率和表面积。的吸附能力进行了测试与两个不同性质的分子：蓝藻毒素（微囊藻毒素-LR）和染料（亚甲基蓝），使用高效液相色谱与紫外检测器（HPLC-UV）和紫外可见光谱，分别。计算出CNF-CD气凝胶对微囊藻毒素LR和亚甲基蓝的平衡吸附量分别为0.078 mg/g和3.46 mg/g，说明CNF-CD气凝胶可用于改善水质。
Interactions at the molecular and surface chemistry are some of the key factors that determine the adsorption capacity of pollutants and emerging contaminants in porous materials. As filtration-based purification of water sources expands, the generation of green materials, such as biopolymers, is the priority. However, to increase the removal capacity, modification of natural polymers appears necessary. Nanomaterials, especially bio-based materials like cellulose nanofibrils, inherently have large surface areas as a consequence of their high aspect ratios. Their capacity to modulate the interactions with contaminants present in water can be modulated by incorporating selective active points, such as hydrophobic cavities, that can further improve their overall adsorption capability. A bio-based material that can fulfil this requirement is beta-cyclodextrin, a cyclic oligosaccharide with seven glucose units, which provides an easy grafting strategy onto cellulose due to structural affinity. Another advantage of using cellulose nanofibril is their film formability, aerogels, and hydrogels without the need of harsh chemicals or processes. In this work, an oligosaccharide with a hydrophobic centre - beta-cyclodextrin - was immobilized onto bleached softwood cellulose nanofibrils, and then used to generate high surface area aerogels with a density of 175 kg/m(3) and porosities above 88%. Charge density titration, Fourier transform infrared with attenuated total reflectance (FTIR-ATR), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), and atomic force microscopy (AFM) characterization techniques were used to assess the successful modification of the fibrils. Inductive coupled plasma mass spectroscopy (ICP-MS) was used to determine the lack of trace chlorine in the material from the grafting process while scanning electron microscopy (SEM) and dynamic vapor sorption (DVS) were used to determine porosity and surface area of the aerogels. The adsorption capacity was tested with two molecules of different natures: a cyanotoxin (microcystin-LR) and a dye (methylene blue), using high-performance liquid chromatography with a UV detector (HPLC-UV) and UV-vis spectroscopy, respectively. The adsorption in equilibrium for CNF-CD aerogels was calculated to be 0.078 mg/g of microcystin-LR and 3.46 mg/g of methylene blue, enlightening its possible use to improve water quality.