scholarly journals Uranium(VI) adsorption on surfactant modified heulandite/clinoptilolite rich tuff

2006 ◽  
Vol 71 (12) ◽  
pp. 1323-1331 ◽  
Author(s):  
Srdjan Matijasevic ◽  
Aleksandra Dakovic ◽  
Magdalena Tomasevic-Canovic ◽  
Mirjana Stojanovic ◽  
Deana Iles
Keyword(s):  
Ion Exchange ◽  
Cation Exchange ◽  
Adsorption Isotherms ◽  
Cation Exchange Capacity ◽  
Exchange Capacity ◽  
Zeolitic Tuff ◽  
Zeolite Surface ◽  
Inorganic Cations ◽  
Maximal Amount ◽  
Ph Values

The adsorption of uranium(VI) on heulandite/clinoptilolite rich zeolitic tuff modified with different amounts (2, 5 and 10 meq/100 g) of hexadecyltrimethyl ammonium (HDTMA) ion was investigated. The organozeolites were prepared by ion exchange of inorganic cations at the zeolite surface with HDTMA ions, and the three prepared samples were denoted as OA-2, OA-5 and OA-10. The maximal amount of HDTMAin the organozeolite OA-10 (10 meq/100 g) was equal to the external cation exchange capacity of the starting material. The results showed that uranium( VI) adsorption on unmodified zeolitic tuff was low (0.34 mg uranium(VI)/g adsorbent), while for the organozeolites, the adsorption increased with increasing amount of HDTMA at the zeolitic surface. The highest adsorption indexes were achieved for the organozeolite OA-10, in which all the surface inorganic cations had been replaced with HDTMA. An investigation of the adsorption of uranium(VI) ions onto organozeolite OA-10 at different pH values (3, 6 and 8) showed that the adsorption index increased with increasing amount of adsorbent in the suspension. Since uranium(VI) speciation is highly dependent on pH, from the adsorption isotherms, it can be seen that uranium(VI) adsorption on organozeolite OA-10 at pH 6 and 8 is well described by a Langmuir type of isotherm, while at pH 3, it corresponds to a Type III isotherm. .

Effects of pH and ionic strength on the cation exchange capacity of soils with variable charge

Soil Research ◽  
1981 ◽  
Vol 19 (1) ◽  
pp. 93 ◽  
Author(s):  
GP Gillman
Keyword(s):  
Ionic Strength ◽  
Cation Exchange ◽  
Cation Exchange Capacity ◽  
Exchange Capacity ◽  
Surface Soils ◽  
Ph Values ◽  
Variable Charge ◽  
Effects Of Ph ◽  
Variable Charge Soils

The cation exchange capacity of six surface soils from north Queensland and Hawaii has been measured over a range of pH values (4-6) and ionic strength values (0.003-0.05). The results show that for variable charge soils, modest changes in electrolyte ionic strength are as important in their effect on caton exchange capacity as are changes in pH values.

The Use of Some Ion-Exchange Sorbing Tracer Cations in Insitu Experiments in High Saline Groundwaters

1994 ◽  
Vol 353 ◽  
Author(s):  
J. Byegård ◽  
G. Skarnemark ◽  
M. Skålberg
Keyword(s):  
Ion Exchange ◽  
Cation Exchange ◽  
Cation Exchange Capacity ◽  
Alkali Metals ◽  
Alkaline Earth ◽  
Exchange Capacity ◽  
Alkaline Earth Metals ◽  
Crushed Granite ◽  
The Difference

AbstractThe possibility to use alkali metals and alkaline earth metals as slightly sorbing tracers in in-situ sorption experiments in high saline groundwaters has been investigated. The cation exchange characteristics of granite and some fracture minerals (chlorite and calcite) have been studied using the proposed cations as tracers. The results show low Kd’s for Na, Ca and Sr (∽0.1 ml/g), while the sorption is higher for the more electropositive cations (Rb, Cs and Ba). A higher contribution of irreversible sorption can also be observed for the latter group of cations. For calcite the sorption of all the tracers, except Ca, is lower compared to the corresponding sorption to granite and chlorite. Differences in selectivity coefficients and cation exchange capacity are obtained when using different size fractions of crushed granite. The difference is even more pronounced when comparing crushed granite to intact granite.

Differential effect of pasture species on the pH and cation exchange capacity of a subsequently cultivated soil

1970 ◽  
Vol 74 (3) ◽  
pp. 453-456 ◽  
Author(s):  
A. J. Rixon
Keyword(s):  
Organic Matter ◽  
Cation Exchange ◽  
Differential Effect ◽  
Cation Exchange Capacity ◽  
Exchange Capacity ◽  
Lower Percentage ◽  
Ph Values ◽  
Cultivated Soil ◽  
The Difference ◽  
Inorganic Fraction

SUMMARYHigher pH values had been established under grass than under clover pastures during a prior pasture phase. The differential effect of pasture species on the pH of the subsequently cultivated soil was reduced in time, but continued to be significant after 4 years.There was greater cation exchange capacity and lower percentage base saturation after clovers than after grasses. The cation exchange capacity of the inorganic fraction of the soil was not affected by the type of pasture and did not change with time. The difference in cation exchange capacity for the cultivated soil was, therefore, due to the difference in the cation exchange capacity of organic matter residual from the clover and grass pastures.

scholarly journals Quantification of permanent and variable charges in reference soils of the State of Pernambuco, Brazil

2014 ◽  
Vol 38 (4) ◽  
pp. 1162-1169 ◽  
Author(s):  
Jailson Cavalcante Cunha ◽  
Hugo Alberto Ruiz ◽  
Maria Betânia Galvão dos Santos Freire ◽  
Víctor Hugo Alvarez V. ◽  
Raphael Bragança Alves Fernandes
Keyword(s):  
Ion Exchange ◽  
Cation Exchange ◽  
Cation Exchange Capacity ◽  
Chloride Solution ◽  
Particle Surface ◽  
Cesium Chloride ◽  
Exchange Capacity ◽  
The State ◽  
Isomorphic Substitution ◽  
Do So

The electrical charges in soil particles are divided into structural or permanent charges and variable charges. Permanent charges develop on the soil particle surface by isomorphic substitution. Variable charges arise from dissociation and association of protons (H+), protonation or deprotonation, and specific adsorption of cations and anions. The aim of this study was to quantify the permanent charges and variable charges of Reference Soils of the State of Pernambuco, Brazil. To do so, 24 subsurface profiles from different regions (nine in the Zona da Mata, eight in the Agreste, and seven in the Sertão) were sampled, representing approximately 80 % of the total area of the state. Measurements were performed using cesium chloride solution. Determination was made of the permanent charges and the charges in regard to the hydroxyl functional groups through selective ion exchange of Cs+ by Li+ and Cs+ by NH4+, respectively. All the soils analyzed exhibited variable cation exchange capacity, with proportions from 0.16 to 0.60 and an average of 0.40 when related to total cation exchange capacity.

scholarly journals Ion Exchange Properties of Novel Hydrous Metal Oxide Materials

1996 ◽  
Vol 432 ◽  
Author(s):  
T. J. Gardner ◽  
L. I. McLaughlin
Keyword(s):  
Ion Exchange ◽  
Metal Oxide ◽  
Cation Exchange ◽  
Transition Metal Oxides ◽  
Cation Exchange Capacity ◽  
High Surface ◽  
Catalyst Support ◽  
High Surface Area ◽  
Exchange Capacity ◽  
Alkali Cations

AbstractHydrous metal oxide (HMO) materials are inorganic ion exchangers which have many desirable characteristics for catalyst support applications, including high cation exchange capacity, anion exchange capability, high surface area, ease of adjustment of acidity and basicity, bulk or thin film preparation, and similar chemistry for preparation of various transition metal oxides. Cation exchange capacity is engineered into these materials through the uniform incorporation of alkali cations via manipulation of alkoxide chemistry. Specific examples of the effects of Na stoichiometry and the addition of SiO2 to hydrous titanium oxide (HTO) on ion exchange behavior will be given. Acid titration and cationic metal precursor complex exchange will be used to characterize the ion exchange behavior of these novel materials.

scholarly journals SINTESIS DAN PERBANDINGAN STRUKTUR, TEKSTUR BENTONIT ALAM DAN BENTONIT TERAKTIVASI ASAM

2016 ◽  
Vol 7 (01) ◽  
pp. 137-140
Author(s):  
Sri Hilma Siregar ◽  
Wirdati Irma
Keyword(s):  
Ion Exchange ◽  
Specific Surface ◽  
Cation Exchange ◽  
Surface Area ◽  
Specific Surface Area ◽  
Cation Exchange Capacity ◽  
Exchange Capacity ◽  
Crystalline Structures ◽  
Activated Bentonite ◽  
Acid Cation

Bentonite is a material that has several layers, which consists of one layer of octahedral and two tetrahedral layers or commonly known as the bentonite mineral that is composed of layers of 2: 1. Bentonite nature in general is less than optimal when used as an adsorbent. This can be overcome by activating the natural bentonite either chemistry or physics. In this study, natural bentonite acid activated. Bentonite activated with HF acid with a variety of 1% -5%. Acid can damage the structure of octahedral layers in the space between the layers. Effect of activation with HF acid cause ion exchange of Al3+, Fe3+, Mg2+ with H+ ions from the acid HF so changes smectite crystalline structures. Activation of bentonite with lead acid cation exchange capacity decreased and significantly increases the specific surface area of 26.893 m2 / g (natural bentonite) to 43.167 m2 / g (activated).

scholarly journals Sorption of pertechnetate anion by cation modified bentonites

2019 ◽  
Vol 322 (3) ◽  
pp. 1771-1776
Author(s):  
D. Buzetzky ◽  
E. M. Kovács ◽  
M. N. Nagy ◽  
J. Kónya
Keyword(s):  
Ion Exchange ◽  
Cation Exchange ◽  
Cation Exchange Capacity ◽  
Metal Ion ◽  
Exchange Process ◽  
Exchange Capacity ◽  
Ion Exchange Process

Abstract Pertechnetate anion sorption was investigated on modified bentonites. Mn-, Cr-, Sn-bentonites were prepared by ion exchange process to sorb radioactive pertechnetate ions. In the case of Mn-, Cr-bentonite the sorb amount of metal ion was 70–90% of the cation exchange capacity of the bentonite which is expected. Interestingly in the case of Sn-bentonite this amount was 1.42 times higher than the cation exchange capacity. On Mn-bentonite the sorption was 35% at pH 5. The removal of pertechnetate ions was 100% on Cr-, Sn-bentonites and the significant sorption was achieved below 650 mV/SHE.

Quantification of Exchangeable Cations in Interlayer of Tsukinuno Sodium-Montmorillonite

2009 ◽  
Vol 1193 ◽  
Author(s):  
Haruo Sato
Keyword(s):  
Ion Exchange ◽  
Cation Exchange ◽  
Exchange Reaction ◽  
Cation Exchange Capacity ◽  
Exchange Capacity ◽  
Exchangeable Cations ◽  
Initial Material ◽  
Ion Exchange Reaction ◽  
Reaction Constant ◽  
Good Agreement

AbstractIn this study, the cation exchange capacity (CEC) and leached exchangeable cations (LC) of montmorillonite purified from bentonite produced in the Tsukinuno bentonite mine, Yamagata, Japan, were measured, and the exchangeable cations in the interlayer of the montmorillonite were discussed. A montmorillonite, in which the soluble minerals were completely removed, was prepared. Kunipia-F and Kunipia-P, for which both bentonites originally contain approximately 100 wt.% montmorillonite, were used as the initial material. All of the measurements were carried out in a N2 atmosphere-controlled glove-box.The CEC values of montmorillonites for both bentonites (100-110 meq/100g) were similar to data conventionally reported, and the sum of LC was also approximately in good agreement with the CEC values. The share of Na+ in the interlayer of montmorillonite calculated from the LC was about 3/4 of the sum of the LC (≍ CEC), and Mg2+ and Ca2+ occupied about 7 and 19 %, respectively. Although montmorillonite in bentonite produced in the Tsukinuno bentonite mine is known as a Na type, the sum of Ca2+ and Mg2+ occupied about 26 % of all exchangeable cations in the interlayer. Based on these data, the ion exchange reaction constant between Na+ and H+ in the interlayer of montmorillonite was calculated to be -0.07. This is nearly 2 orders of magnitude lower than data that are usually adopted.

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