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Particle size effect of layered double hydroxide on the porosity of calcined metal oxide
Applied Clay Science ( IF 5.6 ) Pub Date : 2020-09-01 , DOI: 10.1016/j.clay.2020.105701
Sang-Yong Jung , Bo-Kyung Kim , Shingo Hirata , Miki Inada , Jae-Min Oh

Abstract The structure, porosity, and adsorption properties of mixed metal oxides (MMO) were investigated according to the physical property of the starting materials. Layered double hydroxides (LDH), the pristine MMO, were prepared to have the same composition of Mg2Al(OH)6(CO3)0.5, but with different particle size. The prepared LDH were calcined at 400 °C to obtain MMO named CMO, HMO, and UMO corresponding to the pristine MMO synthesized by coprecipitation, hydrothermal treatment, and urea hydrolysis method, respectively. The particle sizes of CMO, HMO, and UMO were comparable to those of the pristine MMO in the order UMO > HMO > CMO; on the other hand, the crystallite sizes were almost the same as each other, regardless of the pristine MMO. According to the high-resolution transmission electron microscopy and X-ray diffraction, we could suggest that a single particle of MMO was composed of smaller domains of metal oxide crystallite. Consequently, small MMO particle tended to have interparticulate macropore, while large MMO particle had more possibility of containing intraparticulate mesopores, which was cross-confirmed by the N2 adsorption–desorption isotherms. Toluene and water vapor adsorption tests on three different MMO showed that the intraparticulate mesopores were advantageous to adsorb a variety of adsorbate. It was therefore concluded that MMO obtained by calcination of LDH would have high adsorption property when the pristine LDH has large particle dimension, thanks to the large portions of intraparticulate mesopores.

中文翻译:

层状双氢氧化物的粒径对煅烧金属氧化物孔隙率的影响

摘要 根据起始材料的物理性质研究了混合金属氧化物(MMO)的结构、孔隙率和吸附性能。层状双氢氧化物 (LDH),即原始 MMO,制备成具有相同成分的 Mg2Al(OH)6(CO3)0.5,但具有不同的粒径。将制备的LDH在400℃下煅烧得到MMO,命名为CMO、HMO和UMO,分别对应于通过共沉淀、水热处理和尿素水解法合成的原始MMO。CMO、HMO 和 UMO 的粒径与原始 MMO 的粒径相当,顺序为 UMO > HMO > CMO;另一方面,无论原始 MMO 如何,微晶尺寸几乎彼此相同。根据高分辨透射电子显微镜和 X 射线衍射,我们可以认为单个 MMO 颗粒由较小的金属氧化物微晶域组成。因此,小的 MMO 颗粒倾向于具有颗粒间的大孔,而大的 MMO 颗粒更可能含有颗粒内的中孔,这被 N2 吸附-解吸等温线交叉证实。对三种不同 MMO 的甲苯和水蒸气吸附试验表明,颗粒内介孔有利于吸附多种吸附质。因此得出的结论是,当原始 LDH 具有大颗粒尺寸时,通过煅烧 LDH 获得的 MMO 将具有高吸附性能,这要归功于大部分的颗粒内介孔。小 MMO 颗粒倾向于具有颗粒间大孔,而大 MMO 颗粒更可能含有颗粒内的中孔,N2 吸附-解吸等温线交叉证实了这一点。对三种不同 MMO 的甲苯和水蒸气吸附试验表明,颗粒内介孔有利于吸附多种吸附质。因此得出的结论是,当原始 LDH 具有大颗粒尺寸时,通过煅烧 LDH 获得的 MMO 将具有高吸附性能,这要归功于大部分的颗粒内介孔。小 MMO 颗粒倾向于具有颗粒间大孔,而大 MMO 颗粒更可能含有颗粒内的中孔,N2 吸附-解吸等温线交叉证实了这一点。对三种不同 MMO 的甲苯和水蒸气吸附试验表明,颗粒内介孔有利于吸附多种吸附质。因此得出的结论是,当原始 LDH 具有大颗粒尺寸时,通过煅烧 LDH 获得的 MMO 将具有高吸附性能,这要归功于大部分的颗粒内介孔。对三种不同 MMO 的甲苯和水蒸气吸附试验表明,颗粒内介孔有利于吸附多种吸附质。因此得出的结论是,当原始 LDH 具有大颗粒尺寸时,通过煅烧 LDH 获得的 MMO 将具有高吸附性能,这要归功于大部分的颗粒内介孔。对三种不同 MMO 的甲苯和水蒸气吸附试验表明,颗粒内介孔有利于吸附多种吸附质。因此得出的结论是,当原始 LDH 具有大颗粒尺寸时,通过煅烧 LDH 获得的 MMO 将具有高吸附性能,这要归功于大部分的颗粒内介孔。
更新日期:2020-09-01
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