使用声芬顿工艺对硅藻类外壳进行优越的环保清洗：易于制造具有均匀形态和可控尺寸的纳米多孔硅。

Environmentally superior cleaning of diatom frustules using sono-Fenton process: Facile fabrication of nanoporous silica with homogeneous morphology and controlled size.

机构信息

Research Laboratory of Advanced Water and Wastewater Treatment Processes, Department of Applied Chemistry, Faculty of Chemistry, University of Tabriz, 51666-16471 Tabriz, Iran; Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 1627, FI-70211 Kuopio, Finland.

Research Laboratory of Advanced Water and Wastewater Treatment Processes, Department of Applied Chemistry, Faculty of Chemistry, University of Tabriz, 51666-16471 Tabriz, Iran; Department of Materials Science and Nanotechnology Engineering, Faculty of Engineering, Near East University, 99138, Nicosia, TRNC, Mersin 10, Turkey; Institute of Research and Development, Duy Tan University, Da Nang 550000, Viet Nam.

出版信息

Ultrason Sonochem. 2020 Jun;64:105044. doi: 10.1016/j.ultsonch.2020.105044. Epub 2020 Feb 26.

DOI:10.1016/j.ultsonch.2020.105044

PMID:32146334

Abstract

Existing techniques for the preparation of silica structures from diatom cells include cleaning of frustules through baking at high temperature and oxidant cleaning using concentrated sulfuric acid, hydrogen peroxide, nitric acid, or sodium dodecyl sulfate (SDS)/ethylenediaminetetraacetic acid (EDTA). In this study, sono-Fenton (SF) process was examined to prepare nanoporous silica through cleaning diatom frustules, while preserving their structural features. Single colonies of Cyclotella sp. were cultivated in batch mode f/2-enriched seawater. Combination of Fenton process with ultrasonication was found to be more efficient than the sum of individual processes in the removal of organic compounds from Cyclotella sp. structure. The optimized amounts of operational parameters were determined as suspension pH of 3, diatom cell density of 4.8 × 10 cell mL, HO concentration of 60 mM, Fe concentration of 15 mM, ultrasound irradiation power of 400 W and the temperature of 45 °C. The results of energy-dispersive X-ray spectroscopy (EDX) and thermal gravimetry (TG) analyses proved that organic materials covering the cell wall were significantly removed from the frustules through SF process. Scanning electron microscopy (SEM) images showed that after SF treatment, silica nanostructures were produced having uniform pores less than 15 nm in diameter. N adsorption-desorption isotherms demonstrated that almost non-porous structure of diatom frustules became mesoporous during removing the organic matrix. Lipids, amino acids, carbohydrates and organic acids or their oxidized products were identified using GC-MS analysis as the main organic compounds released from diatom cells to the solution after SF treatment. Treated frustules exhibited adsorption capability of 91.2 mg/g for Methylene Blue, which was almost 2.5 times higher than that of untreated frustules (34.8 mg/g).

摘要

现有的从硅藻细胞制备二氧化硅结构的技术包括通过高温烘烤和使用浓硫酸、过氧化氢、硝酸或十二烷基硫酸钠（SDS）/乙二胺四乙酸（EDTA）进行氧化清洁来清洁壳。在这项研究中，研究了声芬顿（SF）工艺，通过清洁硅藻壳来制备纳米多孔二氧化硅，同时保留其结构特征。在 f/2 富化海水中以批处理模式培养了 Cyclotella sp. 的单菌落。发现 Fenton 工艺与超声波的结合比单个工艺的总和更有效地从 Cyclotella sp. 结构中去除有机化合物。确定了优化的操作参数量，悬浮液 pH 值为 3，硅藻细胞密度为 4.8×10 个细胞 mL，HO 浓度为 60 mM，Fe 浓度为 15 mM，超声辐照功率为 400 W，温度为 45°C。能量色散 X 射线光谱（EDX）和热重（TG）分析的结果证明，通过 SF 工艺从壳上显著去除了覆盖细胞壁的有机材料。扫描电子显微镜（SEM）图像显示，SF 处理后，产生了具有小于 15nm 直径的均匀孔的二氧化硅纳米结构。N 吸附-解吸等温线表明，在去除有机基质后，硅藻壳的几乎无孔结构变为介孔。使用 GC-MS 分析鉴定了脂质、氨基酸、碳水化合物和有机酸或其氧化产物作为 SF 处理后从硅藻细胞释放到溶液中的主要有机化合物。处理过的壳表现出对亚甲蓝的吸附能力为 91.2mg/g，几乎是未处理壳（34.8mg/g）的 2.5 倍。