Parameterization and regionalization of Cd sorption characteristics of sandy soils. I. Freundlich type parameters

1998 ◽  
Vol 161 (6) ◽  
pp. 681-687 ◽  
Author(s):  
Günther Springob ◽  
Jürgen Böttcher
1999 ◽  
Vol 79 (2) ◽  
pp. 321-324 ◽  
Author(s):  
T. R. Moore ◽  
L. Matos

We examined the influence of dissolved organic carbon (DOC) source on the sorption of DOC by two clayey and two sandy soils using seven extracts from plant tissues and organic soil horizons. Sorption characteristics, such as null-point DOC concentration, partition coefficient and intercept, were determined over the initial solution concentration range of 0–50 mg DOC L−1. The clayey soils had larger partition coefficients and higher null points than the sandy soils. There was an average threefold variation in null-point DOC concentration and partition coefficient amongst the seven DOC extracts. Fractionation of the DOC samples into humic acid and hydrophobic and hydrophilic acids, bases and neutrals revealed weak relationships between the sorption characteristics and DOC chemistry. Key words: Dissolved organic carbon, sorption, fractionation, humic acid, fulvic acid


2020 ◽  
Vol 66 (No. 4) ◽  
pp. 162-166
Author(s):  
Amer Sunulahpasic ◽  
Sinisa Mitric ◽  
Dragana Sunjka ◽  
Mirjana Zabic ◽  
Tihomir Predic ◽  
...  

In this study, the sorption characteristics of nicosulfuron herbicide in soils from different agricultural regions of Bosnia and Herzegovina, as well as factors influencing the sorption process, were evaluated. The analysis was performed using a batch equilibrium method. The obtained results showed that soils in Bosnia and Herzegovina are very versatile in terms of their characteristics. The Freundlich adsorption coefficient (K<sub>f</sub>) coefficient ranged from 0.027 to 7.388, while the slope of the Freundlich isotherm (1/n) varied from 0.291 to 1.927. In soils with pH 4.31–7.60, 1/n was found to be less than 1 (0.337–0.547), and for the extremely alkaline soil with pH 8.2, 1/n was 1.927. Adsorption of nicosulfuron in the tested soils of Bosnia and Herzegovina was significantly correlated with the sand and silt content in the soil. Multiple linear regression correlating log K<sub>f</sub> with the sand and silt content in the studied soils was also statistically significant (R<sup>2</sup> = 0.951; P = 0.0108). The results of this study indicate that in sandy soils, which are slightly or moderately alkaline, the adsorption of nicosulfuron is very low and only a small amount of nicosulfuron will be adsorbed.


The authors' methodic for assessing the role of chemical and physic-chemical factors during the structure formation of gypsum stone is presented in the article. The methodic is also makes it possible to reveal the synergistic effect and to determine the ranges of variation of controls factors that ensure maximum values of such effect. The effect of a micro-sized modifier based on zinc hydro-silicates on the structure formation of building gypsum is analyzed and corresponding dependencies are found. It is shown that effects of influence of modifier on the properties of gypsum compositions are determined by chemical properties of modifier. Among the mentioned properties are sorption characteristics (which depend on the amount of silicic acid and its state) and physicochemical properties - the ability to act as a substrate during crystal formation. The proposed method can also be extended to other binding substances and materials. This article contributes to the understanding of the processes that occur during the structure formation of composites, which will make it possible to control the structure formation in the future, obtaining materials with a given set of properties.


2020 ◽  
Vol 21 (1) ◽  
pp. 35-44
Author(s):  
Janet L Gehring ◽  
Caitlin Foster ◽  
Alan Yepsen

2012 ◽  
Vol 11 (12) ◽  
pp. 2163-2168
Author(s):  
Alexandra-Dana Chitimus ◽  
Valentin Nedeff ◽  
Emilian Florin Mosnegutu ◽  
Mirela Panainte

Author(s):  
A. Safonov ◽  
N. Andriushchenko ◽  
N. Popova ◽  
K. Boldyrev

Проведен анализ сорбционных характеристик природных материалов (вермикулит, керамзит, перлит, цеолит Трейд ) при очистке кадмий- и хромсодержащих сточных вод с высокой нагрузкой по ХПК. Установлено, что цеолит обладает максимальными сорбционными характеристиками для Cd и Cr и наименьшим биологическим обрастанием. При использовании вермикулита и керамзита или смесей на их основе можно ожидать увеличения сорбционной емкости для Cd и Сr при микробном обрастании, неизбежно происходящем в условиях контакта с водами, загрязненными органическими соединениями и биогенами. При этом биообрастание может повысить иммобилизационную способность материалов для редоксзависимых металлов за счет ферментативных ресурсов бактериальных клеток, использующих их в качестве акцепторов электронов. Эффект микробного обрастания разнонаправленно изменял параметры материалов: для Cr в большинстве случаев уменьшение и для Cd значительное увеличение. При этом дополнительным эффектом иммобилизации Cr является его биологическое восстановление биопленками. Варьируя состав сорбционного материала, можно подбирать смеси, оптимально подходящие для очистки вод инфильтратов с полигонов твердых бытовых отходов с высокой нагрузкой по ХПК и биогенным элементам как при использовании in situ, так и в системах на поверхности.The analysis of the sorption characteristics of natural materials (vermiculite, expanded clay, perlite, Trade zeolite) during the purification of cadmium and chromium-containing leachate with a high COD load was carried out. It was determined that zeolite had the maximum sorption capacity for Cd and Cr and the lowest biological fouling. When using vermiculite and expanded clay or mixtures on their basis, one can expect an increase in the sorption capacity for Cd and Cr during microbial fouling that inevitably occurs during contacting with water polluted with organic compounds and nutrients. In this case biofouling can increase the immobilization properties of materials for redox-dependent metals due to the enzymatic resources of bacterial cells that use them as electron acceptors. The effect of microbial fouling changed the parameters of materials in different directions: for Cr, in most cases, downward, and for Cd, significantly upward. Moreover, chromium biological recovery by biofilms is an additional effect of immobilization. Varying the composition of the sorption material provides for selecting mixtures that are optimally suitable for the purification of leachates from solid waste landfills with high COD and nutrients load, both when used in situ and in surface systems.


Sign in / Sign up

Export Citation Format

Share Document