Sorption of Anionic Pentachlorophenol (PCP) in Aquatic Environments: The Effect of pH

1992 ◽  
Vol 25 (11) ◽  
pp. 41-48 ◽  
Author(s):  
Y. Shimizu ◽  
S. Yamazaki ◽  
Y. Terashima

The sorption of pentachlorophenol (PCP, pKa’ = 4.75) onto natural solids from aqueous phase was investigated by batch sorption experiments. The experimental aqueous phase was prepared for set values of pH (2 to 12) and ionic strength (0.1 M). Experimental results indicated that the sorption decreased with increasing pH over the entire pH range tested. A simple mathematical model, based on the hypotheses that the sorption coefficients of non-ionized and ionized species are different and the pH has only negligible effect on the natural solid characteristics, was applied to the pH range between 6 and 8, and the sorption coefficients (Kd) of both species were estimated. The Kd of ionized species (phenolate anion) was smaller than that of non-ionized species. The Kd of both species had poor correlation to the organic carbon content of natural solids. The Kd, however, correlated well with the swelling clay content and cation exchange capacity of natural solids. These results indicated that the sorption of PCP was not controlled by the organic carbon referenced hydrophobic sorption. For broader pH range (i.e., below 6 or above 8), the dependence of the natural solid characteristics on pH must be additionally included in the model.

1992 ◽  
Vol 26 (1-2) ◽  
pp. 79-87 ◽  
Author(s):  
Y. Shimizu ◽  
N. Takei ◽  
Y. Terashima

The sorption of trichloroethylene (TCE) from vapor phase onto natural solids was investigated by batch sorption experiments. The effects of natural solid characteristics and moisture content on the sorption of TCE vapor were evaluated. As natural solids, six different US EPA soils and sediments were used. The moisture content of each natural solid was adjusted at four different values, including oven-dried condition. The linear sorption coefficients of TCE from the vapor phase (Kd’) were about one to four orders of magnitude greater than those from the aqueous phase. The Kd’ values for the oven-dried natural solids had poor correlation to the organic carbon content of natural solids. These results indicated that the sorption of TCE vapor was not controlled by the organic carbon referenced hydrophobic sorption. The Kd’ values for the oven-dried natural solids, however, correlate well with the cation exchange capacity (CEC) and swelling clay content of natural solids. The interaction of TCE molecules with the exchangeable cations on natural solid surface could be a dominant sorption mechanism. The Kd’ values decreased with increasing the moisture content of natural solids. The water on natural solid surface interferes the vapor-phase sorption of TCE onto the surface cations.


Soil Research ◽  
2000 ◽  
Vol 38 (1) ◽  
pp. 155 ◽  
Author(s):  
C. B. Hedley ◽  
S. Saggar ◽  
B. K. G. Theng ◽  
J. S. Whitton

The specific surface area (SSA) of a range of soils has been measured by adsorption of para-nitrophenol (pNP). These surface soils are representative of the major soil groups of New Zealand, varying in mineralogy, clay and organic carbon contents, and cation exchange capacity (CEC). All of the soils are under pastures of introduced grasses and legumes that have been regularly fertilised and grazed. The SSAs measured by pNP are compared with the values calculated from the clay content, clay mineral composition, and organic carbon content of the soils. Measured SSAs are also related to the air-dry soil moisture contents. There is a good 1:1 relation between measured and calculated SSAs. This correspondence improves when allophanic and smectitic soils are omitted from the relation. The SSAs measured by pNP are also well correlated with the air-dry moisture content and CEC of the soils. When allophanic soils are excluded, a highly significant correlation (r = 0.894; P < 0.001) is obtained between pNP surface area and moisture content of the air-dry soils. When the same relation is applied to an independent set of soils, 89% of the variations in SSA can be accounted for. We suggest that the SSAs of many soils can be reasonably deduced from their air-dry moisture content.


2021 ◽  
Vol 23 (3) ◽  
pp. 368-374
Author(s):  
A. BASUMATARY ◽  

Two hundred fifty geo-referenced surfaces (0-15 cm) soil samples were collected and analysed for macronutrients and micronutrients to study fertility status in soils of Dima Hasao district of Assam and their relationship with some important soil properties. Soils of the district were found to be extremely acidic to slightly acidic in reaction with a low to high organic carbon content and low in cation exchange capacity. The soil of the district indicated that the available nitrogen, phosphorus and potassium status was observed to the tune of 14.0 %,7.2% and 67.2% under low and 86.0 %, 92.8 % and 32.8 %under medium categories, respectively. The overall percent deficient of exchangeable calcium, magnesium and available sulphur in soils was 25.6, 30.4 and 6.8 %, respectively. Based on critical limit, all soils were adequately supplied with DTPA-extractable Fe, Mn and Cu content. In respect of zinc and boron, soils exhibited 90.4 and 73 per cent under sufficient, while, 2.4 and 12 per cent were found deficient in DTPA -Zn and HWS-B, respectively. Soil pH and EC showed positive correlation with macro nutrients and negative correlation with micronutrients. The macro- and micronutrient showed significant positive relation with soil organic carbon and cation exchange capacity.


2020 ◽  
Vol 19 (1) ◽  
Author(s):  
Martin Leue ◽  
Daniel Uteau ◽  
Stephan Peth ◽  
Steffen Beck‐Broichsitter ◽  
Horst H. Gerke

1986 ◽  
Vol 58 (1) ◽  
pp. 1-7
Author(s):  
Raina Niskanen ◽  
Antti Jaakkola

The efficiency of the soil testing method used in Finland for predicting the effective cation-exchange capacity was studied in a material of 430 topsoil samples. The effective cation-exchange capacity was estimated 1) by summation of exchangeable Ca, Mg and acidity displaced by unbuffered 1 M KCI and 2) by summation of exchangeable Ca, Mg, K and Na displaced by neutral 1 M ammonium acetate and exchangeable acidity. In soil testing, Ca, Mg and K were extracted by acid ammonium acetate and soil pH measured in water-suspension. The estimates of the effective CEC were highly correlated and dependent on the clay and organic carbon content and pH(CaCl2) of the soil, the coefficient of multiple determination being over 80 %. Exchangeable Ca was the dominating cation. The proportion of Ca of the effective CEC was about 80 %. Acid ammonium acetate-extractable Ca together with pH(H2O) explained over 80 % of the variation in the effective CEC. For the whole material consisting of mineral soils with great variations in texture, organic carbon content and properties under evaluation, the regression equation predicting the effective CEC (KCI method) was CEC (mval/kg) = 309—56.8pH(H2O) + 0.085Ca(mg/l). Only 16 % of the estimates of the effective CEC calculated with this regression equation deviated more than 15 % from the measured values.


2021 ◽  
Vol 17 (AAEBSSD) ◽  
pp. 147-149
Author(s):  
P.N. Tripathi ◽  
U.S. Mishra ◽  
Pawan Sirothia ◽  
R.P. Singh

Three representative soil pedonsof northern hills of Chhattisgarh, M.P were morphologically studied, characterized and classified. The soils are very deep, colour ranges from brown (10YR5/3) to dark brown (10YR3/3) and very dark greyish brown (10YR3/2) in different horizons. Fe and calcretes are observed in sub surface horizons. The texture in surface soils varied from clay loam to clay while in pedon 2, the texture was observed sandy clay loam throughout the profile. The soils are calcareous and pH ranged from 7.0 to 7.5. The organic carbon content in these soils were (4.4 g kg-1), low to medium (6.1 g kg-1) in surface and decreased with depth. Cation exchange capacity (CEC) were found high in horizons where clay content was more. Based on morphological, physical and chemical properties P1 and P3 were classified as VerticHaplustalfs and pedon (P2) was placed under Typic Haplustepts.


1982 ◽  
Vol 62 (4) ◽  
pp. 657-662 ◽  
Author(s):  
C. WANG

The results of a study which compared some selected soil characteristics of small and large map unit delineations are presented. Color, organic carbon, pH, cation exchange capacity and clay content were measured. Properties, such as pH and CEC of surface soil and pH of subsoil, were found to be significantly different between large and small delineations. Although Brandon is selected to be a simple and relatively uniform map unit, the range of variation was wide for all of the selected soil properties. For each property measured the coefficient of variability was always larger in surface soils than in subsoils. However, variance of measured soil properties did not differ between the two groups of delineations. Consequently, the soil boundary effect is considered to be insignificant for the Brandon unit of the Dalhousie association studied.


2006 ◽  
Vol 41 (3) ◽  
pp. 461-468 ◽  
Author(s):  
Maurílio Fernandes de Oliveira ◽  
Hélio Teixeira Prates ◽  
Derli Prudente Santanna ◽  
Rubem Silvério de Oliveira Júnior

The objective of this work was to study the sorption and desorption of imazaquin, in surface and subsurface soil samples from Brazil. Sorption and desorption steps were carried out using batch equilibration and high performance liquid chromatography analytical routines. The value of Kf,ads was positively correlated with clay content, and negatively correlated with pH of supernatant. Samples from Typic Haplustox, clayey soil profile having high clay content, provided higher Kf,ads values, and negative correlation with organic carbon, silt content, cation exchange capacity and pH.


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