Crystal structure model development for soil clay minerals – II. Quantification and characterization of hydroxy-interlayered smectite (HIS) using the Rietveld refinement technique

Geoderma ◽  
2019 ◽  
Vol 347 ◽  
pp. 1-12 ◽  
Author(s):  
Jan Dietel ◽  
Kristian Ufer ◽  
Stephan Kaufhold ◽  
Reiner Dohrmann
Keyword(s):  
Crystal Structure ◽  
Clay Minerals ◽  
Rietveld Refinement ◽  
Model Development ◽  
Structure Model ◽  
Soil Clay

Crystal structure model development for soil clay minerals – I. Hydroxy-interlayered smectite (HIS) synthesized from bentonite. A multi-analytical study

Geoderma ◽  
2019 ◽  
Vol 347 ◽  
pp. 135-149 ◽  
Author(s):  
Jan Dietel ◽  
Jens Gröger-Trampe ◽  
Marko Bertmer ◽  
Stephan Kaufhold ◽  
Kristian Ufer ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Clay Minerals ◽  
Analytical Study ◽  
Model Development ◽  
Structure Model ◽  
Soil Clay

Isotherms for Aqueous Potassium Adsorption and Characterization of Natural Pyrophyllite

2011 ◽  
Vol 694 ◽  
pp. 682-685
Author(s):  
Hai Feng Chen ◽  
Pei Song Tang ◽  
Min Hong Xu ◽  
Feng Cao
Keyword(s):  
Crystal Structure ◽  
Clay Minerals ◽  
Theoretical Basis ◽  
Adsorption Process ◽  
Potassium Ions ◽  
Adsorption Model ◽  
Natural Minerals ◽  
Silicate Clay ◽  
Size And Morphology

The present investigatory founded an effectiveness of inexpensive and eco-friendly alumina silicate clay minerals, sericitic pyrophyllite (SP), as an adsorbent for the possible application in the absorption of K+. The crystal structure of pyrophyllite, size and morphology were characterized by XRD and SEM. In addition to pyrophyllite, quartz and were also contained in the minerals. The area of lamellar SP was about dozens um2. The results showed that potassium was absorbed on the SP under different pH and concentrations, and the best condition was pH=6, the time of equilibrium absorption = 30 min. It has been found that these natural minerals are effective in removing 55−75% of K+ from 5.0 to 20 mgL-1 KNO3 solutions. The applicability of the Langmuir, Freundlich and Dubinin-Radushkevich adsorption isotherms in each case of potassium was examined separately. We found that the adsorption process was endothermic in the case of SP and the Freundlich adsorption model was to more suitably represent the data. The work could provide the theoretical basis of the study of potassium ions adsorbed by pyrophyllite applying in fertilizer.

scholarly journals Characterization of nickel doped Zn7Sb2O12 spinel phase using Rietveld refinement

2003 ◽  
Vol 18 (3) ◽  
pp. 219-223 ◽  
Author(s):  
L. Gama ◽  
C. O. Paiva-Santos ◽  
C. Vila ◽  
P. N. Lisboa-Filho ◽  
E. Longo
Keyword(s):  
Crystal Structure ◽  
Rietveld Refinement ◽  
Spinel Phase ◽  
Pechini Method ◽  
Polymeric Precursor ◽  
X Ray Diffraction ◽  
Inverse Spinel ◽  
Precursor Method ◽  
X Ray

Zn7Sb2O12 is known to adopt an inverse spinel crystal structure, in which Zn2+ occupies the eight tetrahedral positions and Sb5+ and Zn2+ randomly occupy the 16 octahedral positions. Samples of Zn7−xNixSb2O12 (x=0, 1, 2, 3, and 4) were synthesized using a modified polymeric precursor method, known as the Pechini method. The crystal structure of the powders was characterized by Rietveld refinement with X-ray diffraction data. The results show that for x=0, 1, and 2 Ni substitutes for Zn2+ in the octahedral sites, and that for x=3 and 4 it is assumed that Ni2+ replaces Zn2+ ions in both the octahedral and tetrahedral positions. It is also observed for x=3 and 4 the formation of two spinel phases.

Treatment system response to transient AOX (adsorbable organic halogen) loadings

1997 ◽  
Vol 35 (2-3) ◽  
pp. 85-91
Author(s):  
D. A. Barton ◽  
J. D. Woodruff ◽  
T. M. Bousquet ◽  
A. M. Parrish
Keyword(s):  
Paper Industry ◽  
Model Development ◽  
Operating Conditions ◽  
System Response ◽  
Additional Information ◽  
Organic Halogen ◽  
Aox Removal ◽  
Variable Operating Conditions ◽  
Plant Shutdown

If promulgated as proposed, effluent guidelines for the U.S. pulp and paper industry will impose average monthly and maximum daily numerical limits of discharged AOX (adsorbable organic halogen). At this time, it is unclear whether the maximum-day variability factor used to establish the proposed effluent guidelines will provide sufficient margin for mills to achieve compliance during periods of normal but variable operating conditions within the pulping and bleaching processes. Consequently, additional information is needed to relate transient AOX loadings with final AOX discharges. This paper presents a simplistic dynamic model of AOX decay during treatment. The model consists of hydraulic characterization of an activated sludge process and a first-order decay coefficient for AOX removal. Data for model development were acquired by frequent collection of influent and effluent samples at a bleach kraft mill during a bleach plant shutdown and startup sequence.

Crystal structure analysis of 4-R-phenyl-2,6-dimethyl-3,5-N-(dimethylcarbamoyl)-1,4-dihydropyridines [R=2-nitro (1), 4-methoxy (2) and 3,4-dichloro (3)]

1998 ◽  
Vol 213 (3) ◽  
Author(s):  
M. Bidya Sagar ◽  
K. Ravikumar ◽  
Y. S. Sadanandam
Keyword(s):  
Crystal Structure ◽  
Calcium Channel ◽  
Structure Analysis ◽  
Crystal Structure Analysis ◽  
Calcium Channel Antagonists

AbstractThe crystallographic characterization of the following three calcium channel antagonists is reported here: 2,6-dimethyl-3,5-dicarbamoyl-4-[2-nitro]-1,4-dihydropyridine (

scholarly journals Heteroleptic [Cu(P^P)(N^N)][PF6] Complexes: Effects of Isomer Switching from 2,2′-biquinoline to 1,1′-biisoquinoline

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 185
Author(s):  
Nina Arnosti ◽  
Marco Meyer ◽  
Alessandro Prescimone ◽  
Edwin C. Constable ◽  
Catherine E. Housecroft
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Nmr Spectra ◽  
Phenyl Ether ◽  
Quantum Yields ◽  
Dynamic Processes ◽  
Electrochemical Behaviors ◽  
Ambient Temperatures ◽  
Π Stacking

The preparation and characterization of [Cu(POP)(biq)][PF6] and [Cu(xantphos)(biq)][PF6] are reported (biq = 1,1′-biisoquinoline, POP = bis(2-(diphenylphosphanyl)phenyl)ether, and xantphos = (9,9-dimethyl-9H-xanthene-4,5-diyl)bis(diphenylphosphane). The single crystal structure of [Cu(POP)(biq)][PF6] 0.5Et2O was determined and compared to that in three salts of [Cu(POP)(bq)]+ in which bq = 2,2′-biquinoline. The P–C–P angle is 114.456(19)o in [Cu(POP)(biq)]+ compared to a range of 118.29(3)–119.60(3)o [Cu(POP)(bq)]+. There is a change from an intra-POP PPh2-phenyl/(C6H4)2O-arene π-stacking in [Cu(POP)(biq)]+ to a π-stacking contact between the POP and bq ligands in [Cu(POP)(bq)]+. In solution and at ambient temperatures, the [Cu(POP)(biq)][PF6]+ and [Cu(xantphos)(biq)]+ cations undergo several concurrent dynamic processes, as evidenced in their multinuclear NMR spectra. The photophysical and electrochemical behaviors of the heteroleptic copper (I) complexes were investigated, and the effects of changing from bq to biq are described. Short Cu···O distances within the [Cu(POP)(biq)]+ and [Cu(xantphos)(biq)]+ cations may contribute to their very low photoluminescent quantum yields.

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