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A Facile Preparation of Ambient Pressure–Dried Hydrophilic Silica Aerogels and Their Application in Aqueous Dye Removal
Frontiers in Materials ( IF 2.6 ) Pub Date : 2020-04-29 , DOI: 10.3389/fmats.2020.00152
Xianghua Yang , Zhixu Wu , Haifeng Chen , Qixuan Du , Lin Yu , Ruiyang Zhang , Ying Zhou

Highly porous hydrophilic silica aerogels (SAs) are potentially excellent adsorbents in aqueous media, which are generally synthesized via a standard sol–gel method followed by the relatively complex and specialized high pressure–requiring supercritical fluid drying process. Herein, a facile and novel synthetic method applying ambient pressure–drying technology for the rapid preparation of hydrophilic SAs is reported, and they are simply soaked with metal cation solutions without the need of traditional surface modification or supercritical fluid drying process. Chemical and physical properties of the hydrophilic SAs were characterized and compared with a trimethylchlorosilane (TMCS)-modified hydrophobic silica aerogel. In addition to the integrity and low shrinkage of the as-prepared products, Fourier transform infrared (FTIR) spectra and integrated thermal analyzer (ITA) results revealed the presence of hydroxyl groups as well as the absence of multitudinous hydrophobic groups on the silica surface after soaking. Field emission scanning electron microscope (FE-SEM) and Brunauer–Emmett–Teller (BET) measurements confirmed the mesopores inside the aerogel skeleton. Among the tested metal cations, the Mg2+-soaked SAs demonstrated the best pore properties (pore diameter 9.35 nm and pore volume 1.09 cc/g), and the Fe3+-soaked ones got the biggest surface area (855.62 m2/g) in contrast to other metal cations. Rhodamine B and Methylene blue solutions are used to check the absorption ability of the SAs in aqueous media, in which the best adsorption capacity for Rhodamine B and Methylene blue reached 2.8 and 40.4 mg/g, respectively, implying their potential application in aqueous pollutant removal.



中文翻译:

常压干燥的亲水性二氧化硅气凝胶的简便制备及其在去除染料中的应用

高度多孔的亲水性二氧化硅气凝胶(SAs)在水性介质中可能是极好的吸附剂,通常通过标准的溶胶-凝胶法合成,然后通过相对复杂且专门的高压要求的超临界流体干燥过程合成。本文报道了一种利用环境压力干燥技术快速制备亲水性SAs的简便新颖的合成方法,只需将它们用金属阳离子溶液浸泡即可,而无需传统的表面改性或超临界流体干燥工艺。表征了亲水性SA的化学和物理性质,并与三甲基氯硅烷(TMCS)改性的疏水性二氧化硅气凝胶进行了比较。除了所制备产品的完整性和低收缩性外,傅立叶变换红外(FTIR)光谱和集成热分析仪(ITA)结果表明,浸泡后,二氧化硅表面上存在羟基,也没有大量疏水基团。场发射扫描电子显微镜(FE-SEM)和Brunauer-Emmett-Teller(BET)测量证实了气凝胶骨架内部的中孔。在测试的金属阳离子中,镁2+浸透的SAs表现出最佳的孔隙性能(孔径9.35 nm,孔体积1.09 cc / g),Fe 3+浸透的SAs具有最大的表面积(855.62 m 2 / g),与其他金属阳离子相比。罗丹明B和亚甲基蓝溶液用于检查SAs在水性介质中的吸收能力,其中罗丹明B和亚甲基蓝的最佳吸附容量分别达到2.8和40.4 mg / g,这暗示着它们在去除水污染物中的潜在应用。

更新日期:2020-04-29
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