Shape- and size- dependent desorption kinetics and surface acidity on nano-SnO2

The desorption kinetic parameters (the desorption activation energy (Ed) and the desorption pre-exponential factor (A)) and the surface acidity (the strength and number of acid sites) of spherical and octahedral...

Adsorption–Desorption Characteristics of ss-DNA on 2D TpTta-COF Studied by Fluorescently Labeled Oligonucleotides

Being the newest member of the 2D materials family, 2D-nanosheet possesses many distinctive physical and chemical properties resulting in a wide range of potential applications. Recently, it was discovered that 2D COF can adsorb single-stranded DNA (ss-DNA) efficiently as well as usefully to quench fluorophores. These properties make it possible to prepare DNA-based optical biosensors using 2D COF. While practical analytical applications are being demonstrated, the fundamental understanding of binding between 2D COF and DNA in solution received relatively less attention. In this work, we carried out a systematic study to understand the adsorption and desorption kinetic, mechanism, and influencing factors of ss-DNA on the surface of 2D COF. We demonstrated that shorter DNAs are adsorbed more rapidly and bind more tightly to the surface of 2D COF. The adsorption is favored by a higher pH. The different buffer types also can affect the adsorption. In Tris-HCl solution, the adsorption reached highest efficiency. By adding the complementary DNA (cDNA), desorption of the absorbed DNA on 2D COF can be achieved. Further, desorption efficiency can also be exchanged by various surfactant in solution. These findings are important for further understanding of the interactions between DNA and COFs and for the optimization of DNA and COF-based devices and sensors.

Study of the Influence of the V in the Zr2Fe Alloy from Hydrogen Storage on Thermodynamic Properties

Hydrogen storage in its solid state is one of the main challenges for mobile and stationary applications. Some metal hydrides are potential candidates for energy storage. This is an experimental research, which represents a contribution to the study of Hydrogen storage in its solid state, by studying the influence of the proportional substitution of V for Zr in the stoichiometric ratio Zr2-XVXFe (X=0.0, 0.1 y 0.2). Results indicate that the synthesis process generates a multi-phase type microstructure, and the absorption and desorption kinetic is less than 5 minutes at room temperature, in line with the parameters established by the United States Department of Energy; however, it is clear that the desorption capacity decreases.

Desorption and Re-Adsorption of Procion Red MX-5B Dye on Alumina-Activated Carbon Composite

The alumina-activated carbon has the ability to adsorb and desorb the procion red MX-5B. The research evaluated the influence of desorption agent, contact time, and temperature on desorption process of procion red MX-5B dye with alumina-activated carbon composite and the adsorption capacity of the composite after desorption process. The desorption agents used in desorption process were solution with pH 2−10, H2O2 30 % (v/v), methanol 70% (v/v) and ethanol 70% (v/v). The variation of contact time was in the range from 30 to 270 min and the temperature was set between 30−75 °C. The result concluded that the highest desorption efficiency up to 98.56% was achieved using ethanol 70% (v/v) for 240 min at 45 °C. The desorption kinetic followed the pseudo-first-order with the release constant (kdes) of 6.56 × 10-2 min-1. The SEM micrograph showed there is a more porous surface on the composite after the desorption compared to before the desorption. The EDX analysis indicated that alumina content in the composite was reduced after desorption process. FTIR spectra of the composite before and after desorption process showed a peak of Al−O at 592 and 590 cm-1 which was proved that alumina still exists in the composite after the desorption process. The alumina-activated carbon composite was re-used to adsorb procion red MX-5B dye. After three times of desorption and re-adsorption process, the capacity adsorption was decreased from 12.38 to 7.38 mg/g.