“…Schematic 1 shows the formation process of novel urchin-like γ-Al 2 O 3 hierarchical microspheres. At first, 1D NH 4 Al(OH) 2 CO 3 nanowires is easy to form in the presence of low concentration urea [27][28][29], due to + NH 4 and -OH ions can prefer to adsorb on some of the crystal planes of AACH nanocrystallites, it promote the nucleus grow along a preferential direction to form AACH nanowires. And increasing urea concentration will produce more -OH in the solution, which results in the decrease of particle size, so the rod-like surface of AACH start separating from each other [27], various separated nanowires originated from a same nucleus grow radially and form the urchin-like hierarchical microspheres.…”
In this paper, we present a convenient hydrothermal method to synthesize hierarchical microspheres consisting of ammonium aluminum carbonate hydroxide (AACH) nanowires with a diameter of about 400 nm and length ∼50 μm on aluminum foils. After calcination at 900°C, hierarchical γ-Al 2 O 3 microspheres with mesoporous structures were obtained successfully, which possess a high specific surface area of 124 m 2 g −1 and high porosity of 0.71cm 3 g −1 . The possible formation mechanism was discussed. The as-prepared mesoporous γ-Al 2 O 3 hierarchical nanostructures exhibited improved adsorption performance towards Congo red in aqueous solution, 90% CR could be removed rapidly in 20 min, and its saturation adsorption capacity in 80 mg l −1 Congo red can reach to 180 mg g −1 , it suggests that the hierarchical γ-Al 2 O 3 microspheres with unique microstructure have potential in wastewater treatment.
“…Schematic 1 shows the formation process of novel urchin-like γ-Al 2 O 3 hierarchical microspheres. At first, 1D NH 4 Al(OH) 2 CO 3 nanowires is easy to form in the presence of low concentration urea [27][28][29], due to + NH 4 and -OH ions can prefer to adsorb on some of the crystal planes of AACH nanocrystallites, it promote the nucleus grow along a preferential direction to form AACH nanowires. And increasing urea concentration will produce more -OH in the solution, which results in the decrease of particle size, so the rod-like surface of AACH start separating from each other [27], various separated nanowires originated from a same nucleus grow radially and form the urchin-like hierarchical microspheres.…”
In this paper, we present a convenient hydrothermal method to synthesize hierarchical microspheres consisting of ammonium aluminum carbonate hydroxide (AACH) nanowires with a diameter of about 400 nm and length ∼50 μm on aluminum foils. After calcination at 900°C, hierarchical γ-Al 2 O 3 microspheres with mesoporous structures were obtained successfully, which possess a high specific surface area of 124 m 2 g −1 and high porosity of 0.71cm 3 g −1 . The possible formation mechanism was discussed. The as-prepared mesoporous γ-Al 2 O 3 hierarchical nanostructures exhibited improved adsorption performance towards Congo red in aqueous solution, 90% CR could be removed rapidly in 20 min, and its saturation adsorption capacity in 80 mg l −1 Congo red can reach to 180 mg g −1 , it suggests that the hierarchical γ-Al 2 O 3 microspheres with unique microstructure have potential in wastewater treatment.
“…Urchin-like spherule particles of Al 2 O 3 were synthesized by the hydrothermal method described in detail in Ref. 28 . SEM images of the particles are depicted in Fig.…”
Section: Experimental: Materials and Methodsmentioning
confidence: 99%
“… Figure 1 SEM images of the urchin-like Al 2 O 3 particles, synthesized according to the protocol, supplied in Ref. 28 . ( A ) Scale bar is 10 μm.…”
Section: Experimental: Materials and Methodsmentioning
confidence: 99%
“…Urchin-like particles were obtained by the method of hydrothermal synthesis, from an aqueous-alcoholic solution of aluminum salts taken at a ratio of Al 2 (SO 4 ) 3 :Al(NO 3 ) 3 = 80:20 ml%/mol%. The molar ratios of the components of the synthesis were Al 3+ /CO(NH 2 ) 2 /H 2 O/i-PrOH = 1:2:100:5, the synthesis scheme is described in detail in 28 .…”
Section: Experimental: Materials and Methodsmentioning
Omniphobic and icephobic twin-scale surfaces based on the “urchin”-like fluorinated Al2O3 particles are presented. Combined effect of hierarchical topography and fluorination supplied to the surfaces omniphobic and icephobic properties. The study of the stability of the Cassie wetting state is reported. High apparent contact angles were accompanied with the low contact angle hysteresis and high stability of the Cassie air trapping wetting state. Time delay of the ice crystallization as high as $$88\pm 5$$
88
±
5
min was established when compared to the ice formation on flat aluminum and non-fluorinated “urchin”-like surfaces. Crystallized water droplets formed on the reported nano-structured surfaces were easily blown out by the air jet with the velocity of $$v=3.0\pm 1.0$$
v
=
3.0
±
1.0
m/s, (which is markedly lower than that common for exploitation of aircrafts and turbines). Heated “urchin”-like surfaces completely restored their omniphobic and icephobic surfaces after thawing. Qualitative analysis of water freezing is supplied.
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