Multicomponent ion exchange in zeolites. Part 1.—Equilibrium properties of the sodium/calcium/magnesium–zeolite A system

Author(s):  
Kevin R. Franklin ◽  
Rodney P. Townsend
Author(s):  
Z. I. Khazheeva ◽  
S. S. Sanzhanova

The Dzhida ore field in the Zakamensk district of Buryatia features high concentration of mineralization within a small area. The Dzhida deposit is composed of complex ore. The ore field contains commercial-value primary deposits: Pervomai stockwork of molybdenum, Kholtoson tungsten lode and Inkur stockwork of tungsten. The Modonkul river catchment basin lies inside the Dzhida ore field. A real threat to the town of Zakamensk is created by manmade sand-bulk (old) tailings and slurry dump. By now, the concentrated flow of natural and man-made sand enters the low terrace and floodplain of the Modonkul river in the form of a talus train. This study is focused on the influence of the mine drainage effluent and the Inkur tributary on the water chemistry in the Modonkul river. 80 water samples were taken from the surface layer 0-0.5 m thick at five stations. Physicochemical indices of water were measured at the water sampling points, and the water chemistry was analyzed in a laboratory. In the background conditions, cations and anions in the Modonkul water chemistry range in decreasing order as follows: Са2+ > Mg2+ > Na++К+ и HCO - > SO 2- > Cl-. In the zone of mixture of natural and mine process water, the chemistry changes: from hydrocarbonate to sulfate (anion), from calcium-magnesium to sodium-calcium (cation). Downstream the natural chemistry changes to the hydrocabonate-sulfate composition, with prevailing content of calcium in cations. Iron content of water lowers 3-4 times after influx of mine effluents, while the contents of Mn, Zn, Co and Cd grow and then decrease downstream.


Clay Minerals ◽  
2012 ◽  
Vol 47 (1) ◽  
pp. 81-92 ◽  
Author(s):  
S. Tomić ◽  
N. Rajić ◽  
J. Hrenović ◽  
D. Povrenović

AbstractNatural zeolitic tuff from Brus (Serbia) consisting mostly of clinoptilolite (about 90%) has been investigated for the reduction of the Mg concentration in spring water. The sorption capacity of the zeolite is relatively low (about 2.5 mg Mg g-1for the initial concentration of 100 mg Mg dm-3). The zeolitic tuff removes Mg from water solutions by ion exchange, which has been demonstrated by energy dispersive X-ray analysis (EDS). The extent of ion exchange was influenced by the pH and the initial Mg concentration. Kinetic studies revealed that Lagergen's pseudo-second order model was followed. Intra-particle diffusion of Mg2+influenced the ion exchange, but it is not the rate-limiting step. Rather than having to dispose of the Mg-loaded (waste) zeolite, a possible application was tested. Addition to a wastewater with a low concentration of Mg showed that it could successfully make up for the lack of Mg micronutrient and, accordingly, enabled the growth of phosphate-accumulating bacteriaA. Junii, increasing the amount of phosphate removed from the wastewater.


Geology ◽  
1989 ◽  
Vol 17 (6) ◽  
pp. 552 ◽  
Author(s):  
T. E. Cerling ◽  
B. L. Pederson ◽  
K. L. Von Damm

2017 ◽  
Vol 52 (5) ◽  
pp. 311-318
Author(s):  
Renata Gimenez Sampaio Zocche ◽  
Suziane Antes Jacobs ◽  
Norton Victor Sampaio ◽  
Velci Queiróz de Souza ◽  
Ivan Ricardo Carvalho ◽  
...  

Abstract: The objective of this work was to characterize 'Cabernet Sauvignon' wines made from grapes cultivated in the region of Bagé, RS, Brazil, during three crop seasons. A randomized complete block design was carried out with three treatments and three replicates.The evaluations were performed for the 2004, 2007, and 2008 growing seasons. 'Cabernet Sauvignon' wines of the 2004, 2008, and 2009 harvests differed for the following parameters: density, alcoholic content, total acidity, pH, reducing sugars, OD 420, 520, and 620, color intensity, total anthocyanins, total polyphenols, sodium, calcium, magnesium, manganese, copper, iron, rubidium, phosphorus, methanol, propanol, 2-methyl-l-propanol, 2, 3 - methyl-l-butanol, and sum of alcohols. 'Cabernet Sauvignon' has potential to be produced in the Bagé region, and to help it to become a wine growing region in Brazil.


2016 ◽  
Vol 23 (4) ◽  
pp. 375-380
Author(s):  
P. Manohar Reddy ◽  
Ravy Lakshmi ◽  
Febin Prabhu Dass ◽  
Swamiappan Sasikumar

AbstractSodium calcium silicate (Na2CaSiO4) is a bioactive silicate with Na2O, CaO and SiO2 as its basic components, which is similar to that of the composition of bioactive glasses. In the present study, pure sodium calcium silicate was synthesized by rapid combustion technique, and the synthesized sample was characterized by powder X-ray diffraction to check the phase purity. The scaffolds were prepared by varying the ratio of sodium calcium silicate and polyvinyl alcohol, and the apatite-formation ability of the scaffolds was examined by soaking them in a simulated body fluid. The results revealed the formation of hydroxyapatite on the surface of the scaffold after 5 days, which is found to be rapid when compared with the bioactivity of the calcium silicates and calcium magnesium silicates. The scaffolds were also loaded with ciprofloxacin as a model drug and analyzed for its drug release profile using UV spectrophotometer. The release profile did not vary with the change in bioceramic-to-biopolymer ratio, and 60% of the drug was released in 10 days, which is within the appreciable range for a targeted drug delivery system. Moreover, the experimental and simulated values of the release kinetics were compared by applying the existing mathematical model.


Author(s):  
D. Drummond ◽  
A. Jonge ◽  
L. V. C. Rees

1981 ◽  
Vol 12 (38) ◽  
Author(s):  
F. F. ASSAD ◽  
V. M. SABET ◽  
S. N. SRIVASTAVA

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