KAUST-8晶体尺寸的调控及其吸水性能

Size Control of KAUST-8 Crystal Grains and Their Water Adsorption Property

通过采用向合成液中加入醇类添加剂的方法调控MOFs材料粒径,成功制备了纳米级金属有机骨架材料KAUST-8。采用X射线衍射(XRD)、热场发射扫描电子显微镜(SEM)及粒度分析等检测手段对KAUST-8的晶体结构、形貌和尺寸进行了表征,并探索了不同尺寸KAUST-8晶体的吸水性能。结果表明:随着介质中乙醇的体积分数从0增加到91%,KAUST-8晶体的粒径从10μm减小到500 nm;将乙醇替换成正丁醇,且正丁醇在介质中的体积分数为91%,KAUST-8晶体粒径进一步减小至约300 nm。KAUST-8晶体对水的吸附性能随着其晶体粒径的减小而增强。在25℃下,纯水中粒径300 nm的KAUST-8晶体对水的吸附性能最好,达581.7 mg/g,优于常见的吸水剂3A、4A、5A及13X分子筛的吸水性能。

The nano-sized metal organic framework material KAUST-8 was successfully prepared by adding alcohol additives into the synthetic solution to control the particle size of MOFs material.The crystal structure,morphology and size of KAUST-8 crystal grains were characterized with X-ray diffraction(XRD),thermal field emission scanning electron microscopy(SEM)and particle size analysis.In addition,water adsorption capabilities of different size KAUST-8 crystals were also investigated.Experimental results show that the particle size of KAUST-8 crystals can decrease from 10μm to 500 nm as ethanol volume fraction increases from 0 to 91%.When n-butanol is used instead of ethanol,and n-butanol volume fraction in the medium is kept as 91%,the particle size of KAUST-8 crystals can be further reduced to about 300 nm.It was found that the smaller size KAUST-8 crystals have higher water adsorption capability.300 nm KAUST-8 crystals exhibit the best water adsorption capacity in pure water,i.e.,581.7 mg/g at 25℃.It is better than most of commercial available absorbents,such as 3A,4A,5A and 13X molecular sieves.