نتایج جستجو برای: desorption kinetic

تعداد نتایج: 107828  

F. Farzaneh

Hydrothermal synthesis of nickel-chitosan hybrid  has  been accomplished using Ni(CH3COO)2,4H2O, chitosan and water as starting material, template and solvent respectively, followed by calcination at 800 and 900˚C to provide nanoporous NiO800  and NiO900. The solid products were characterized by X-ray diffraction (XRD), nitrogen adsorption-desorption, scanning electron microscopy (SEM) and Four...

Journal: :Journal of hazardous materials 2008
Chao-Yin Kuo

This study evaluates exhausted carbon nanotubes regenerated by desorption processes using 1mM NaOH and microwave irradiation processes. Kinetic analyses of re-adsorption were performed using pseudo first- and second-order models. Regression results revealed that a pseudo first-order model accurately captured re-adsorption kinetics. The regeneration efficiency was 28, 30, 35 and 44% at 18, 28, 3...

2017

The desorption of methanol and dimethyl ether has been studied over fresh and hydrocarbon-occluded ZSM-5 catalysts with Si/Al ratios of 25, 36 and 135 using a temporal analysis of products reactor. The catalysts were characterized by XRD, SEM, N2 physisorption and pyridine FT-IR. The crystal size increases with Si/Al ratio from 0.10 to 0.78 μm. The kinetic parameters were obtained using the Red...

Journal: :Physical chemistry chemical physics : PCCP 2014
Ankur Jain Takayuki Ichikawa Shotaro Yamaguchi Hiroki Miyaoka Yoshitsugu Kojima

A number of known catalysts, which have been proven to be very effective for several hydrogen species, were studied in order to determine their effects on the hydrogen ab/desorption properties of KSiH3. Among all the catalysts used in this work, mesoporous Nb2O5 is found to be quite effective, with a reduction in activation energy from 142 kJ mol(-1) for pristine KSi to 63 kJ mol(-1) for mesopo...

2017
Xiaotao Zhang Yinan Hao Ximing Wang Zhangjing Chen

A low-cost activated carbon (XSBLAC) prepared from XanthocerasSorbifoliaBungehull via chemical activation was investigated to determine its adsorption and desorption properties for zinc(II) ions from aqueous solutions. XSBLAC was characterized based on its N₂-adsorption/desorption isotherm, EDX, XRD, SEM and FTIR results. An adsorption study was conducted in a series of experiments to optimize ...

Journal: :The Journal of chemical physics 2012
Christine Hahn Junjun Shan Ying Liu Otto Berg Aart W Kleijn Ludo B F Juurlink

We describe the use of a polished, hollow cylindrical nickel single crystal to study effects of step edges on adsorption and desorption of gas phase molecules. The crystal is held in an ultra-high vacuum apparatus by a crystal holder that provides axial rotation about a [100] direction, and a crystal temperature range of 89 to 1100 K. A microchannel plate-based low energy electron diffraction/r...

1998

The fate of Pb in the environment is highly dependent on sorption and desorption reactions on solid surfaces. In this study Pb sorption and desorption kinetics on γ-Al2O3 at pH 6.50, I ) 0.1 M, and [Pb]initial ) 2 mM were investigated using both macroscopic and spectroscopic measurements. X-ray absorption fine structure (XAFS) spectroscopy revealed a Pb-Al bond distance of 3.40 Å, consistent wi...

2017
Xiaoting Wang Ying Chen Yajun Zheng Zhiping Zhang

The dynamic pore systems and high surface areas of flexible metal-organic framework materials make them excellent candidates to be used in different kinds of adsorption processes. However, the adsorption and desorption behaviors of therapeutic drugs on metal-organic frameworks in solution are not fully developed. Here, we systematically investigated the adsorption and desorption behaviors of a ...

2006
T. Paszko

studies on adsorption, desorption and reaction kinetics of carbendazim in grey-brown podzolic soil derived from loamy sand (Albic luvisls), grey-brown podzolic soil derived from silt (Haplic luvisols) and brown soil derived from sandy clay loam (Haplic Cambisols) were carried out. Five concentrations of carbendazim (5.0, 3.8, 2.6, 1.0 and 0.2 μg ⋅ cm-3) in 0.01 mol ⋅ dm-3 CaCl2 were used for th...

2002
Matthias K. Gobbert Samuel G. Webster Timothy S. Cale

We present a Boltzmann equation-based model for transport and reaction in micrometer-scale features such as those found in integrated circuit fabrication. We focus on the adsorption and desorption of one species to understand the transient responses to step changes at the reactor scale. The transport model has no adjustable parameters; the assumptions are detailed. Adsorption and desorption rea...

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