60CO and 137CS Activity of Nearshore Lake Ontario Sediments in the Vicinity of the Pickering Nuclear Generating Complex

1988 ◽  
Vol 23 (3) ◽  
pp. 396-407 ◽  
Author(s):  
D. W. Rodgers ◽  
R. S. McKinley
Keyword(s):  
Cation Exchange Capacity ◽  
Lake Ontario ◽  
137Cs Activity ◽  
Distribution Coefficients ◽  
Exchange Capacity ◽  
Gamma Activity ◽  
Widespread Distribution ◽  
Adsorption Affinity ◽  
Order Of Magnitude ◽  
60Co Activity

Abstract Detectable 137Cs activity (<1 - 27 Bq/kg dry wt.) was widely distributed in sediments from a series of nearshore transects along Lake Ontario near Pickering Nuclear Generating Station (NGS) ‘A’. In contrast, detectable 60Co activity (<1 - 14 Bq/Kg dry wt.) was largely restricted to transects located near the discharge of Pickering ‘A’ NGS. The widespread distribution of 137Cs is consistent with diffuse input of the radionuclide through fallout, while the restricted distribution of 60Co indicates a localized input of this radionuclide. Adsorption distribution coefficients (Kd’s) of 60Co and 137Cs varied by more than an order of magnitude among representative sediments. Although Kd’s of both radionuclides were correlated with cation exchange capacity and particle size, neither the observed gamma activity nor the corresponding Kd were important in describing 60Co or 137Cs Kd’s. Thus factors other than adsorption affinity alone may be required to account for the distribution of these radionuclides in nearshore Lake Ontario sediments.

scholarly journals Halloysite Composites with Fe3O4Particles: The Effect of Impregnation on the Removal of Aqueous Cd(II) And Pb(II)

Mineralogia ◽  
2017 ◽  
Vol 48 (1-4) ◽  
pp. 107-126 ◽  
Author(s):  
Paulina Maziarz ◽  
Jakub Matusik
Keyword(s):  
Adsorption Capacity ◽  
Cation Exchange Capacity ◽  
Chemical Precipitation ◽  
Exchange Capacity ◽  
Point Of Zero Charge ◽  
Precipitation Method ◽  
Removal Mechanism ◽  
X Ray Diffraction ◽  
X Ray ◽  
Adsorption Affinity

Abstract In this study, halloysite-Fe3O4composites were synthesized by a chemical-precipitation method to facilitate magnetic separation of the sorbents from aqueous solution. The research focused on the effect of Fe3O4phase on the halloysite sorption properties. The X-ray diffraction (XRD) results confirmed successful deposition of Fe3O4particles on a halloysite surface. They showed that the coating with Fe3O4particles enhanced the halloysite adsorption affinity toward Cd(II) and Pb(II). The highest adsorption capacity was determined for the composites having 10% of the surface deposited with Fe3O4. In this case, the adsorption capacity for Cd(II) and Pb(II) was 33 and 112 mmol·kg-1, respectively. The point of zero charge (pHPZC) and desorption results indicated that the removal mechanism of metals is mainly related to chemisorption involving reaction with hydroxyls of either halloysite or Fe3O4phase. The ion exchange is of limited importance due to the low cation exchange capacity (CEC) of halloysite - Fe3O4composites.

scholarly journals Adsorption of Organic Compounds on to Bentonites Modified with Single or Dual Quaternary Ammonium Cations

2003 ◽  
Vol 21 (2) ◽  
pp. 135-148 ◽  
Author(s):  
R. Gönülşen ◽  
N. Yıldız ◽  
A. Çalımlı
Keyword(s):  
Quaternary Ammonium ◽  
Cation Exchange Capacity ◽  
Competitive Adsorption ◽  
Inorganic Ions ◽  
Exchange Capacity ◽  
Mineral Surface ◽  
Adsorption Mechanisms ◽  
Inorganic Cations ◽  
Quaternary Ammonium Cations ◽  
Adsorption Affinity

The adsorption of benzoic acid, hydroquinone and toluene on to bentonites modified with single or dual quaternary ammonium cations was studied. Thus, the mineral surface of the bentonite was modified by replacing the inorganic ions with four quaternary ammonium cations, i.e. tetramethylammonium (TMA), benzyltriethylammonium (BTEA), hexadecyltrimethylammonium (HDTMA) and octadecyltrimethylammonium (ODTMA). The inorganic cations on the bentonite were exchanged with the quaternary ammonium cations to the respective extent of ca. 35% TMA, 75% BTEA, 83% HDTMA, 90% ODTMA, 35% TMA/54% HDTMA, 35% TMA/58% ODTMA and 75% BTEA/12% HDTMA of the cation-exchange capacity (CEC) of the bentonite, resulting in a change in the surface properties from hydrophilic to organophilic. The experimental results obtained indicated that the adsorption affinity on dual-modified bentonites was generally lower than that on single-modified bentonites. It was concluded that this resulted from two different adsorption mechanisms and the competitive adsorption of binary solutes.

scholarly journals Modified Sorbents Based on Granular Glauconite for Natural Waters Purification from Radio Nuclides

2016 ◽  
pp. 99
Author(s):  
Keyword(s):  
Natural Waters ◽  
Active Agent ◽  
Distribution Coefficients ◽  
Exchange Capacity ◽  
Static Exchange Capacity ◽  
Henry's Law ◽  
Henry’S Law ◽  
Liquid Phases ◽  
Order Of Magnitude ◽  
Modified Sorbents

Expediency of the modified sorbents application for natural waters purification from cesium and strontium radio nuclides has been demonstrated. Possibility to use granular glauconite as a carrier for sorption-active agent films has been considered. Results of the research of 137Cs and 90Sr radio nuclides sorption reduction from water solutions with modified materials based on granular glauconite in static and dynamic conditions are presented. A cesium and strontium concentration range within which the reduced elements distribution between solid and liquid phases is in accordance with Henry’s law has been determined. Within the Henry’s law action area the modified sorbents distribution coefficients are Kd = (1.0±0.2)·104 ml/g for cesium and Kd = (1.6±0.7)·103 ml/g for strontium. It has been shown that the modified sorbents are an order of magnitude higher that initial granular glauconite in terms of their kinetic and capacitive characteristics. Static exchange capacity of the modified granular glauconite for 137Cs is estimated as 144 mg/g, for 90Sr as 42 mg/g. Dynamic exchange capacity of the modified sorbent is more than 11 mg/g for 137Cs, the value of the detained water phase volume exceeds 22 000 ml (≈ 7000 columnar volumes). The obtained experimental data can be applied for development of technological schemes for natural water sources rehabilitation on any radiation-contaminated territories.

scholarly journals Environmental behaviors of (E)-Pyriminobac-methyl in agricultural soils

2021 ◽  
Author(s):  
Wenwen Zhou ◽  
Haoran Jia ◽  
Lang Liu ◽  
Baotong Li ◽  
Yuqi Li ◽  
...  
Keyword(s):  
Organic Matter ◽  
Cation Exchange Capacity ◽  
Agricultural Soils ◽  
Organic Matter Content ◽  
Exchange Capacity ◽  
Matter Content ◽  
Environmental Behaviors ◽  
Adsorption Affinity ◽  
Groundwater Systems ◽  
Adsorption Desorption

Abstract. (E)-Pyriminobac-methyl (EPM), a pyrimidine benzoic acid esters herbicide, has a high potential as weedicide; nevertheless, its environmental behaviors are still not well understood. In this study, we systematically investigated for the first time the adsorption–desorption, degradation, and leaching behaviors of EPM in agricultural soils from five exemplar sites in China (characterized by different physicochemical properties) through laboratory simulation experiments. The EPM adsorption–desorption results were well fitted by the Freundlich model (R2 > 0.9999). In the analyzed soils, the Freundlich adsorption (i.e., Kf-ads) and desorption (i.e., Kf-des) coefficients of EPM varied between 0.85–32.22 mg1−1/n L1/n kg−1 and between 0.78–5.02 mg1−1/n L1/n kg−1, respectively. Moreover, the degradation of EPM reflected first-order kinetics: its half-life ranged between 37.46–66.00 d depending on the environmental conditions, and abiotic degradation was predominant in the degradation of this compound. The mobility of EPM in the five soils varied from immobile to highly mobile. The groundwater ubiquity score ranged between 0.9765–2.7160, indicating that EPM posed threat to groundwater quality. Overall, the results of this study demonstrate the easy degradability of EPM, as well as its high adsorption affinity and low mobility in soils with abundant organic matter content and high cation exchange capacity. Under such conditions, there is a relatively low contamination risk for groundwater systems in relation to this compound. At the same time, due to its slow degradation, EPM has a low adsorption affinity and tends to be highly mobile in soils poor in organic matter content and with low cation exchange capacity. Under such conditions, there is a relatively high contamination risk for groundwater systems in relation to this compound. Overall, our findings provide a solid basis for predicting the environmental impacts of EPM.

Sorption Behavior of Radium and Actinium on Soils

2000 ◽  
Vol 663 ◽  
Author(s):  
Yoshiaki Sakamoto ◽  
Shinichi Takebe ◽  
Hiromichi Ogawa ◽  
Susumu Muraoka ◽  
Tomoaki Ishii ◽  
...  
Keyword(s):  
Cation Exchange ◽  
Cation Exchange Capacity ◽  
Soil Surface ◽  
Distribution Coefficients ◽  
Exchange Capacity ◽  
Soil Samples ◽  
Sorption Behavior ◽  
Migration Behavior ◽  
Batch Method ◽  
Sand Column

ABSTRACTDistribution coefficients of 226Ra and 227Ac on soils and tuff have been obtained by a batch method. The distribution coefficients of Ra on loam, two kinds of sand and tuff were 28m3/kg, 0.45m3/kg, 0.19m3/kg and 1.9m3/kg, respectively. A linear relationship between the distribution coefficients of Ra on each soil and Cation Exchange Capacity(CEC) of each soil was obtained to suggest cation exchange sorption reaction of Ra2+ on soil surface. Sorption-migration behavior of Ra in sand column has been studied. Most of Ra remained in the column after passing of 5,000 pore volume of the column, showing several times the distribution coefficients of Ra than that by the batch method. The distribution coefficients of 227Ac on the soil samples were in the range from 1m3/kg to 10m3/kg.

EVALUASI PERUBAHAN KUALITAS TANAH PADA LAHAN BEKAS PENAMBANGAN NIKEL DI PULAU GEBE

2018 ◽  
Vol 4 (1) ◽  
Author(s):  
Mardi Wibowo
Keyword(s):  
Organic Carbon ◽  
Cation Exchange ◽  
Cation Exchange Capacity ◽  
Exchange Capacity ◽  
Mining Activity ◽  
Evaluation Activity ◽  
Land Quality ◽  
Environment Quality

Since year 1977 until 2005, PT. ANTAM has been exploited nickel ore resources at Gebe Island – Center ofHalmahera District – North Maluku Province. Mining activity, beside give economically advantages also causedegradation of environment quality espicially land quality. Therefore, it need evaluation activity for change ofland quality at Gebe Island after mining activity.From chemical rehabilitation aspect, post mining land and rehabilitation land indacate very lack and lackfertility (base saturated 45,87 – 99,6%; cation exchange capacity 9,43 – 12,43%; Organic Carbon 1,12 –2,31%). From availability of nutrirnt element aspect, post mining land and rehabilitation land indicate verylack and lack fertility (nitrogen 0,1 – 1,19%). Base on that data, it can be concluded that land reclamationactivity not yet achieve standart condition of chemical land.Key words : land quality, post mining lan

Equilibrium Sorptions in Heterogeneous Ion Exchange Membranes

1992 ◽  
Vol 57 (9) ◽  
pp. 1905-1914
Author(s):  
Miroslav Bleha ◽  
Věra Šumberová
Keyword(s):  
Experimental Data ◽  
Ion Exchange ◽  
Total Content ◽  
Distribution Coefficients ◽  
Exchange Capacity ◽  
Ion Exchange Membranes ◽  
Ion Exchange Capacity ◽  
Equilibrium Sorption ◽  
Inhomogeneity Factor

The equilibrium sorption of uni-univalent electrolytes (NaCl, KCl) in heterogeneous cation exchange membranes with various contents of the ion exchange component and in ion exchange membranes Ralex was investigated. Using experimental data which express the concentration dependence of equilibrium sorption, validity of the Donnan relation for the systems under investigation was tested and values of the Glueckauf inhomogeneity factor for Ralex membranes were determined. Determination of the equilibrium sorption allows the effect of the total content of internal water and of the ion-exchange capacity on the distribution coefficients of the electrolyte to be determined.

scholarly journals Effect of different soil and weather conditions on efficacy, selectivity and dissipation of herbicides in sunflower

2020 ◽  
Vol 66 (No. 9) ◽  
pp. 468-476
Author(s):  
Miroslav Jursík ◽  
Martin Kočárek ◽  
Michaela Kolářová ◽  
Lukáš Tichý
Keyword(s):  
Cation Exchange Capacity ◽  
Chenopodium Album ◽  
Soil Layer ◽  
Weather Conditions ◽  
Growing Season ◽  
Application Rate ◽  
Exchange Capacity ◽  
Vertical Transport ◽  
Application Rates ◽  
High Precipitation

Six sunflower herbicides were tested at two application rates (1N and 2N) on three locations (with different soil types) within three years (2015–2017). Efficacy of the tested herbicides on Chenopodium album increased with an increasing cation exchange capacity (CEC) of the soil. Efficacy of pendimethalin was 95%, flurochloridone and aclonifen 94%, dimethenamid-P 72%, pethoxamid 49% and S-metolachlor 47%. All tested herbicides injured sunflower on sandy soil (Regosol) which had the lowest CEC, especially in wet conditions (phytotoxicity 27% after 1N application rate). The highest phytotoxicity was recorded after the application of dimethenamid-P (19% at 1N and 45% at 2N application rate). Main symptoms of phytotoxicity were leaf deformations and necroses and the damage of growing tips, which led to destruction of some plants. Aclonifen, pethoxamid and S-metolachlor at 1N did not injure sunflower on the soil with the highest CEC (Chernozem) in any of the experimental years. Persistence of tested herbicides was significantly longer in Fluvisol (medium CEC) compared to Regosol and Chernozem. Dimethenamid-P showed the shortest persistence in Regosol and Chernozem. The majority of herbicides was detected in the soil layer 0–5 cm in all tested soils. Vertical transport of herbicides in soil was affected by the herbicide used, soil type and weather conditions. The highest vertical transport was recorded for dimethenamid-P and pethoxamid (4, resp. 6% of applied rate) in Regosol in the growing season with high precipitation.  

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