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.

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.

Cation and Anion Sorption Capability of Organophilic Bentonite

1997 ◽  
Vol 506 ◽  
Author(s):  
J. Bors ◽  
St. Dultz ◽  
B. Riebe
Keyword(s):  
Cation Exchange ◽  
Surface Charge ◽  
Cation Exchange Capacity ◽  
Particle Surface ◽  
Exchange Capacity ◽  
Negative Particle ◽  
Strontium Ions ◽  
Wyoming Bentonite

ABSTRACTSorption experiments were performed with iodide, cesium and strontium ions on MX-80 Wyoming-bentonite treated with hexadecylpyridinium (HDPy+) in amounts equivalent to 0.2 - 4.0 times the cation exchange capacity (CEC) using 125I- 134Cs+ and 85Sr2+ as tracers. In HDPy-bentonite, iodide exhibited increasing adsorption, while cesium and strontium ions showed decreasing adsorption with increasing organophilicity. It was also found that the Cs+affinity to original and HDPy-bentonite was considerably higher than that of Sr2+ ions. HDPy+ uptake in increasing concentrations resulted in a pronounced expansion of the basal spacings (d002 reflex at 2.78 nm) and in a change of the negative particle surface charge to positive values.

scholarly journals Pedogenesis in the Barreiras Formation Under Climates of Rio Grande do Norte, Brazil

2019 ◽  
Vol 11 (16) ◽  
pp. 19
Author(s):  
Lunara G. da S. Rêgo ◽  
Jéssia J. A. da Silva ◽  
Carolina M. M. Souza ◽  
Jeane C. Portela ◽  
Isadora N. B. M. de Moura ◽  
...  
Keyword(s):  
Cation Exchange ◽  
Cation Exchange Capacity ◽  
Clay Fraction ◽  
Rio Grande ◽  
Exchange Capacity ◽  
Climatic Conditions ◽  
The State ◽  
Sample Collection ◽  
X Ray Diffraction ◽  
Diagnostic Horizons

In Brazil, the state of Rio Grande do Norte has an important coastal zone and coastal Tableland areas along the Barreiras Formation, but there are few studies to locate and characterize soils with cohesive character. Therefore, this work was carried out to characterize pedons in the western and eastern mesoregions of the state, located in the Barreiras Formation and with different climatic conditions. The profile description and sample collection were carried out in March and April 2016. The characteristics of the profile identified were the sequence of horizons and their depth, soil color, texture, structure, consistency, and transition between horizons. The physical analyzes were of soil density and texture. The chemical analyzes consisted of: pH in water and in KCl, contents of available P, Na+, K+, Ca2+, Mg2+, potential acidity, and total organic carbon. Indices obtained were: base sum, effective cation exchange capacity, cation exchange capacity at pH 7.0, base saturation, exchangeable aluminum saturation, and exchangeable sodium percentage. The profiles were classified up to the fourth categorical level. The mineralogical assembly was identified in the clay fraction of the diagnostic horizons. The identification of the minerals was performed by X-ray diffraction. The pedons of the two regions presented distinct characteristics and pedogenesis, occurring laterization in the pedons of the western mesoregion and podzolization in the pedons of the eastern mesoregion, both without presence of cohesive character as a diagnostic attribute.

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. .

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).

Sign in / Sign up

Export Citation Format

Share Document