22. Physical adsorption on low energy solids. II. Adsorption of nitrogen, argon, carbon tetrafluoride, and ethane on polypropolyene

Vacuum ◽  
1965 ◽  
Vol 15 (1) ◽  
pp. 42
Keyword(s):  
Physical Adsorption ◽  
Low Energy ◽  
Carbon Tetrafluoride ◽  
Adsorption Of Nitrogen

scholarly journals Sorption and Diffusion Properties of H- and Modified Forms of ZSM-5 Zeolites

1996 ◽  
Vol 13 (6) ◽  
pp. 495-508 ◽  
Author(s):  
P. Hudek ◽  
D. Bobok ◽  
A. Smiešková ◽  
Z. Židek
Keyword(s):  
Physical Adsorption ◽  
Gravimetric Method ◽  
Equilibrium Concentration ◽  
Sorption Isotherms ◽  
Effective Diffusivity ◽  
Micropore Volume ◽  
Unit Cell ◽  
Adsorption Of Nitrogen ◽  
Effective Diffusivities ◽  
Modified Forms

The sorption properties of samples of H-ZSM-5 zeolite and their forms modified with P, B and Mg were determined by the physical adsorption of nitrogen and evaluated by BET isotherm and t-plot methods. The diffusivities of the samples were measured using a new flow gravimetric method involving the sorption of p- and o-xylenes. The BET specific surface area decreased from 358 m2/g to 35–90 m2/g mainly because of a decrease in micropore volume as determined by the t-plot method. The rate of sorption of p-xylene on all the samples investigated followed Fick's second law of diffusion, leading to an effective diffusivity of ca. 1.7 × 10−11 m2/s, irrespective of whether the H-form or the modified forms were investigated. The sorption isotherms for o-xylene showed some unusual steps. Values for the effective diffusivities decreased from 2.6 × 10−12 m2/s for the H-form to 2.0–2.3 × 10−12 m2/s for the modified forms. The equilibrium concentration of o-xylene at P/P0 = 0.1 was only 0.38–0.68 mol/unit cell, while that of p-xylene was 4.40–5.98 mol/unit cell.

Potential Evaluation of Gray Clay as Adsorbent of Heavy Metals Zinc (II) and Lead (II)

2014 ◽  
Vol 798-799 ◽  
pp. 622-627
Author(s):  
Wellington Siqueira Lima ◽  
José Vanderley Nascimento Silva ◽  
Aline Cadigna Lima Patrício ◽  
Guilherme Costa Oliveira ◽  
Meiry Glaúcia Freire Rodrigues
Keyword(s):  
Heavy Metals ◽  
Factorial Design ◽  
Metal Removal ◽  
Physical Adsorption ◽  
X Ray Diffraction ◽  
X Ray ◽  
Removal Capacity ◽  
Adsorption Of Nitrogen ◽  
Potential Evaluation ◽  
Good Percentage

The problems caused by contamination of heavy metals generate a growing need to implement technologies to reduce or eliminate them. This work aims to evaluate the potential of gray clay, the process of removal of zinc and lead from synthetic effluents in finite bath system. The clay was characterized by: X-ray diffraction, X-ray Spectroscopy Energy Dispersive and Physical Adsorption of Nitrogen. The tests were performed finite bath following a 22 factorial design, with the variables: pH and initial concentrations of metal. The clays were evaluated for their removal capacity and rate of metal removal. After the characterization and evaluation, it was found that the gray clay comprises clay of the groups of kaolinite and mica. The results of the factorial design shown that the adsorption of the metals zinc and lead can be developed with good percentage of removal.

Sign in / Sign up

Export Citation Format

Share Document