scholarly journals Adsorption Characteristics of Lead-, Barium- and Hydrogen-Rich Clinoptilolite Mineral

2003 ◽  
Vol 21 (4) ◽  
pp. 309-317 ◽  
Author(s):  
Fehime Cakicioglu-Ozkan ◽  
Semra Ulku
Keyword(s):  
Water Adsorption ◽  
Adsorption Properties ◽  
Adsorption Mechanisms ◽  
Adsorption Data ◽  
Vapour Adsorption ◽  
Water Vapour Adsorption ◽  
Rich Material ◽  
Static Conditions ◽  
Treatment Water

The carbon dioxide and water vapour adsorption properties of local clinoptilolite-rich material, both as the original and as lead-, barium- and hydrogen-rich forms, were examined. The lead- and barium-rich forms were prepared by treatment of the original clinoptilolite with Pb(NO3)2 and BaCl2 respectively, while the hydrogen-rich form was prepared by NH4Cl and heat treatment. Water and CO2 adsorption experiments were conducted in a volumetric system under static conditions, with low-pressure adsorption data being used for the characterization of the natural, Pb-rich, Ba-rich and H-rich clinoptilolite samples. Although the existence of barium-exchange was not noted, an appreciable decrease in CO2 adsorption was observed with the Pb-rich and H-rich forms due to a decrease in the electrostatic interaction between the surface and the adsorbate. Application of the Dubinin–Astakhov equation to the water adsorption data established the existence of micropores of different sizes that exhibited different adsorption mechanisms.

scholarly journals Factors Influencing the Kinetics of Water Vapour Adsorption on Activated Carbons

2021 ◽  
Vol 23 (3) ◽  
pp. 191
Author(s):  
Y. Boutillara ◽  
L. Richelet ◽  
L.F. Velasco ◽  
P. Lodewyckx
Keyword(s):  
Water Vapour ◽  
Activated Carbons ◽  
Kinetic Constant ◽  
Ambient Conditions ◽  
Experimental Conditions ◽  
Adsorption Mechanisms ◽  
Vapour Adsorption ◽  
Water Vapour Adsorption ◽  
The Impact ◽  
Kinetics Of

The performance of porous carbon materials as sorbents is often compromised by the presence of humidity. Studying the kinetics of water vapour adsorption on activated carbons will undeniably help to overcome this issue. This has been approached in this work by evaluating the influence of several operational factors on the dynamic adsorption of water vapour in these materials. Specifically, different carbon types, particle sizes, air flows and ambient conditions (temperature and relative humidity (RH)) were systematically investigated. The impact of each isolated parameter on both the maximum water uptake and the uptake rate was analyzed by fitting the experimental data to the Linear Driving Force (LDF) kinetic model. The results show that except for the particle size, the studied variables play a role in the water sorption kinetics, although to a different extent. It was also confirmed that the LDF model can adequately describe the kinetics of water vapour adsorption independently of the experimental conditions. Finally, the complete water vapour adsorption process can be described by this model, obtaining a different value of the kinetic constant for the sequential stages, involving different adsorption mechanisms.

Differential heat of water adsorption for montmorillonite, kaolinite and allophane

Clay Minerals ◽  
1989 ◽  
Vol 24 (3) ◽  
pp. 505-512 ◽  
Author(s):  
S. Iwata ◽  
F. Izumi ◽  
A. Tsukamoto
Keyword(s):  
Water Vapour ◽  
Water Adsorption ◽  
Adsorption Process ◽  
Dominant Role ◽  
Equilibrium Constants ◽  
Adsorbed Water ◽  
Differential Heat ◽  
Clay Surface ◽  
Vapour Adsorption ◽  
Water Vapour Adsorption

AbstractDifferential heat of water vapour adsorption for Cs+-saturated montmorillonite, kaolinite and allophane was measured over a low relative humidity range from 10−4 to 10−1. Two interactions (clay surface atom-water and counterion-water) are mainly involved in the water vapour adsorption process. To assess the affinity of water to the clay surface, the amounts of adsorbed water and the differential heat due to Cs+ were estimated from equilibrium constants in the gas phase reactions. It is tentatively concluded that (i) a dominant role of water adsorption due to the Cs+-water interaction in the adsorption process is evident only for montmorillonite; (ii) the affinity of water to the clay surface is strongest for allophane and weakest for montmorillonite.

scholarly journals A first-principles characterization of water adsorption on forsterite grains

2013 ◽  
Vol 371 (1994) ◽  
pp. 20110582 ◽  
Author(s):  
Abu Md Asaduzzaman ◽  
Slimane Laref ◽  
P. A. Deymier ◽  
Keith Runge ◽  
H.-P. Cheng ◽  
...  
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Water Adsorption ◽  
Gas Adsorption ◽  
Dissociative Adsorption ◽  
Single Site ◽  
Adsorption Mechanisms ◽  
Comprehensive Picture ◽  
Dual Site

Numerical simulations examining chemical interactions of water molecules with forsterite grains have demonstrated the efficacy of nebular gas adsorption as a viable mechanism for water delivery to the terrestrial planets. Nevertheless, a comprehensive picture detailing the water-adsorption mechanisms on forsterite is not yet available. Towards this end, using accurate first-principles density functional theory, we examine the adsorption mechanisms of water on the (001), (100), (010) and (110) surfaces of forsterite. While dissociative adsorption is found to be the most energetically favourable process, two stable associative adsorption configurations are also identified. In dual-site adsorption, the water molecule interacts strongly with surface magnesium and oxygen atoms, whereas single-site adsorption occurs only through the interaction with a surface Mg atom. This results in dual-site adsorption being more stable than single-site adsorption.

Hexavalent chromium removal from water: adsorption properties of in natura and magnetic nanomodified sugarcane bagasse

2021 ◽  
Author(s):  
Thais Eduarda Abilio ◽  
Beatriz Caliman Soares ◽  
Julia Cristina José ◽  
Priscila Aparecida Milani ◽  
Geórgia Labuto ◽  
...  
Keyword(s):  
Hexavalent Chromium ◽  
Sugarcane Bagasse ◽  
Water Adsorption ◽  
Adsorption Properties ◽  
Chromium Removal

Preparation and Characterization of Carbon Supported Nano-Nickel and its Sorption Behavior for Zinc from Aqueous Solutions

2012 ◽  
Vol 510-511 ◽  
pp. 271-276 ◽  
Author(s):  
Tayyaba Asim ◽  
R. Ahmed ◽  
M.S. Ansari
Keyword(s):  
Morphological Study ◽  
Aqueous System ◽  
Effect Of Temperature ◽  
Vacuum Drying ◽  
Sorption Behavior ◽  
Nickel Deposition ◽  
Adsorption Data ◽  
Nano Nickel ◽  
The Mean

Nickel deposited on carbon has been used as adsorbent to recover Zn (II) from aqueous system. The adsorbent was synthesized by depositing nickel nitrate on carbon under inert conditions and decomposing it to nickel by raising the temperature, washing and vacuum drying. Various techniques including XRD, FTIR, and SEM were employed for its characterization. FTIR showed that the nickel deposition enhanced the carbon functionalization due to presence of OH, C=O and C-O groups.Average crystallite size ofabout 9 nm was determined from XRD. Nickel deposition resulted in further division particles as indicated from the morphological study. Zn (II) was subjected to adsorptionon the synthesized adsorbent. It was observed that the rate of adsorption increased significantly on the nickel deposited carbon than the carbon alone. Morris-Weber, Lagergren and Reichenberg models were applied to find out the type and rate of adsorption employingfirst and second order rate equations.The adsorption data were applied toLangmuir, Freundlich and D-R isotherms and values of isotherm constants were calculated and were higher for Ni/C than carbon alone. The mean free energy of zinc sorption on carbon and Ni/C are 16.67 and 18.26 kJmol-1 which shows chemisorption. Thermodynamic studies were done to find out the effect of temperature on sorption. Positive values of ΔH and negative values of ΔG show endothermic and spontaneous type of sorption.

Sign in / Sign up

Export Citation Format

Share Document