Enthalpy and interfacial free energy changes of water capillary condensed in mesoporous silica, MCM-41 and SBA-15

2006 ◽  
Vol 8 (27) ◽  
pp. 3223 ◽  
Author(s):  
Shigeharu Kittaka ◽  
Shinji Ishimaru ◽  
Miki Kuranishi ◽  
Tomoko Matsuda ◽  
Toshio Yamaguchi
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yige Guo ◽  
Bin Chen ◽  
Ying Zhao ◽  
Tianxue Yang

AbstractAntibiotics are emerging pollutants and increasingly present in aquaculture and industrial wastewater. Due to their impact on the environment and health, their removal has recently become a significant concern. In this investigation, we synthesized nano zero-valent iron-loaded magnetic mesoporous silica (Fe-MCM-41-A) via precipitation and applied the adsorption of oxytetracycline (OTC) from an aqueous solution. The effects of competing ions such as Na+, Ca2+ and Cu2+ on the adsorption process under different pH conditions were studied in depth to providing a theoretical basis for the application of nanomaterials. The characterization of the obtained material through transmission electron microscopy demonstrates that the adsorbent possesses hexagonal channels, which facilitate mass transfer during adsorption. The loaded zero-valent iron made the magnetic, and was thus separated under an applied magnetic field. The adsorption of OTC onto Fe-MCM-41-A is rapid and obeys the pseudo-second-order kinetic model, and the maximum adsorption capacity of OTC is 625.90 mg g−1. The reaction between OTC and Fe-MCM-41-A was inner complexation and was less affected by the Na+. The effect of Ca2+ on the adsorption was small under acidic and neutral conditions. However, the promotion effect of Ca2+ increased by the increase of pH. Cu2+ decreased the removal efficiencies continuously and the inhibitory effects decrease varied with the increase of pH. We propose that surface complexing, ion-exchange, cationic π-bonding, hydrogen bonding, and hydrophobicity are responsible for the adsorption of OTC onto Fe-MCM-41-A.


Author(s):  
Wevernilson F. de Deus ◽  
Bruna M. de França ◽  
Josué Sebastian B. Forero ◽  
Alessandro E. C. Granato ◽  
Henning Ulrich ◽  
...  

2011 ◽  
Vol 143 (1) ◽  
pp. 174-179 ◽  
Author(s):  
Marília R. Mello ◽  
Delphine Phanon ◽  
Gleiciani Q. Silveira ◽  
Philip L. Llewellyn ◽  
Célia M. Ronconi

RSC Advances ◽  
2015 ◽  
Vol 5 (8) ◽  
pp. 5494-5500 ◽  
Author(s):  
Xin Yu Ming Dong ◽  
Yan Yan Li ◽  
Feng Wei ◽  
Yu Zhou ◽  
Shi Lu Zhou ◽  
...  
Keyword(s):  

Menthol could be adsorbed in as-synthesized MCM-41 at 373 K, open stored in ambient for 30 days and released at 333 K.


2002 ◽  
Vol 731 ◽  
Author(s):  
Z. Guo ◽  
W. Sha

AbstractVarious theories have been developed to describe the diffusion-controlled growth of precipitates with shapes approximating needles or plates. The most comprehensive one is due to Ivantsov, Horvay and Cahn, and Trivedi (HIT theory), where all the factors that may influence the precipitate growth, i.e. diffusion, interface kinetics and capillarity, are accounted for within one equation. However, HIT theory was developed based on assumptions that transformation strain/stress and interfacial free energy are isotropic, which are not true in most of the real systems. An improved growth theory of precipitates of needle and plate shapes was developed in the present study. A new concept, the compression ratio, was introduced to account for influences from the anisotropy of transformation strain/stress and interfacial free energy on the precipitate morphology. Experimental evidence supports such compression effect. Precipitate growth kinetics were quantified using this concept. The improved HIT theory (IHIT theory) was then applied to study the growth of Widmanstatten austenite in ferrite in Fe-C-Mn steels. The calculated results agree well with the experimental observations.


2021 ◽  
Vol 314 ◽  
pp. 172-177
Author(s):  
Yuta Sasaki ◽  
Yousuke Hanawa ◽  
Masayuki Otsuji ◽  
Naozumi Fujiwara ◽  
Masahiko Kato ◽  
...  

Damage-free drying becomes increasingly difficult with the scaling of semiconductor devices. In this work, we studied a new sublimation drying technology for 3nm node and beyond. In order to investigate the collapse factor by conventional sublimation drying, we observed the pattern with cryo-SEM and revealed that the collapse occurred when the liquid film on the substrate solidified. Based on this result, we considered that it was important to deposit a solidified film uniformly from the substrate side to suppress collapse. Two key process parameters were evaluated to achieve the uniform formation of the solidified film. One is interfacial free energy and the other is film thickness of solution just before solidification. By optimizing two key parameters, it was successfully demonstrated to suppress pattern collapse of challenging devices. In this paper, we report on a new drying method: sublimation drying by LPD (Liquid-phase deposition).


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