scholarly journals Sorption of benzothiazoles onto sandy aquifer material under equilibrium and nonequlibrium conditions

2014 ◽  
Vol 79 (1) ◽  
pp. 89-100 ◽  
Author(s):  
Marijana Kragulj ◽  
Jelena Trickovic ◽  
Bozo Dalmacija ◽  
Ivana Ivancev-Tumbas ◽  
Anita Leovac ◽  
...  
Keyword(s):  
Organic Matter ◽  
Sorption Isotherms ◽  
Column Experiments ◽  
Sorption Mechanism ◽  
Desorption Process ◽  
Sorption Behaviour ◽  
Freundlich Model ◽  
Aquifer Material ◽  
Nonequilibrium Conditions ◽  
Sandy Aquifer

In this study, the sorption behaviour of 1,3-benzothiazole (BT) and 2-(methylthio)benzothiazole (MTBT) was investigated on Danube geosorbent under equilibrium and nonequilibrium conditions. All sorption isotherms fitted well with the Freundlich model (R2=0.932-0.993). The results showed that organic matter of the Danube geosorbent has a higher sorption affinity for the more hydrophobic MTBT compared to BT. However, sorption-desorption experiments showed that MTBT was more easily desorbed than BT molecules, which indicates the importance of absorption relative to adsorption in the overall sorption mechanism of MTBT. In general, molecules of BT and MTBT were more easily desorbed in the lower concentration range, which resulted in an increase in the hysteresis indices with increasing concentrations. Column experiments revealed that retention of the investigated compounds on the aquifer material followed the compound?s hydrophobicity. BT showed a lower retention, in accordance with its lower sorption affinity obtained in the static experiments, while MTBT showed a greater sorption affinity, and thus had a longer retention time on the column. Thus during transport BT represent greater risk for groundwaters than MTBT. These results have increased our understanding of benzothiazoles sorption and desorption process which represent one of the most important factors which influence the behaviour of organic compounds in the environment.

Sorption of phenols onto sandy aquifer material: the effect of dissolved organic matter (DOM)

2005 ◽  
Vol 39 (5) ◽  
pp. 933-941 ◽  
Author(s):  
Fariba Amiri ◽  
Hilmar Börnick ◽  
Eckhard Worch
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Aquifer Material ◽  
Sandy Aquifer

scholarly journals High mercury sorption in low organic matter aquifer material using column experiments.

2021 ◽  
Author(s):  
David McLagan ◽  
Carina Esser ◽  
Lorenz Schwab ◽  
Jan Pietrucha ◽  
Jan Wiederhold ◽  
...  
Keyword(s):  
Organic Matter ◽  
Column Experiments ◽  
Aquifer Material ◽  
High Mercury

Uranium and vanadium sorption by chitosan and derivatives

1994 ◽  
Vol 30 (9) ◽  
pp. 183-190 ◽  
Author(s):  
E. Guibal ◽  
I. Saucedo ◽  
M. Jansson-Charrier ◽  
B. Delanghe ◽  
P. Le Cloirec
Keyword(s):  
Particle Size ◽  
Sorption Capacity ◽  
Glutaric Acid ◽  
Sorption Isotherms ◽  
Experimental Results ◽  
Sorption Mechanism ◽  
Freundlich Model ◽  
Surface Control ◽  
The Poor ◽  
Langmuir And Freundlich Models

The modification of chitosan, by grafting of oxo-2-glutaric acid, allows its sorption performance to be increased. This enhancement of uptake ability is observed in overall sorption capacity and specificity in sorbing particular metals. This work focuses on the sorption of uranium (VI) and vanadium (V). The sorption isotherms are studied. The experimental results are described according to the Langmuir and Freundlich models. It was shown that uranium sorption is best described by the Freundlich model, while vanadium sorption is difficult to model. The influence of the particle size, significant in the case of uranium, but not for vanadium, shows that the sorption mechanism is not the same for the two metals : surface control is predominant in the case of uranium, due to the poor porosity of the sorbents. The control of overall sorption capacity is related to the chemistry of the metal and polymer : the appearance of hydrolyzed species and protonation of the polymer.

scholarly journals Lindane sorption and desorption behaviour on sediment organic matter

2013 ◽  
Vol 78 (6) ◽  
pp. 883-895 ◽  
Author(s):  
Jelena Trickovic ◽  
Ivana Ivancev-Tumbas ◽  
Marijana Kragulj ◽  
Miljana Prica ◽  
Dejan Krcmar ◽  
...  
Keyword(s):  
Organic Matter ◽  
Humic Acid ◽  
Sorption Isotherms ◽  
Sediment Organic Matter ◽  
Sorption Coefficient ◽  
Freundlich Model ◽  
Nonlinear Sorption ◽  
Soils And Sediments ◽  
Desorption Hysteresis ◽  
Physical Conformation

The work is concerned with the sorption and desorption behaviour of lindane on four humic acid fractions (HAs) and two humin fractions, sequentially extracted from Ludas lake sediment. All sorption isotherms, fitted to a Freundlich model, were nonlinear. The isotherm linearity increased from 0.757 for the first extracted HA to 0.944 for the ninth HA showing a positive correlation with atomic H/C ratio, while a negative correlation between sorption coefficient and aliphaticity of the isolated HAs was observed. It has been shown that the sorption processes may be strongly influenced by the physical conformation of and accessibility to sediment organic matter (SOM), as demonstrated by high Koc and low n values of humin samples. Despite exhibiting the most nonlinear sorption isotherms, humin samples did not show a pronounced sorption-desorption hysteresis, while the most significant hysteresis was observed for three HA samples. These results support the hypothesis that the aromatic domains in SOM influence strongly the sorption and desorption behaviour of lindane. Our findings may be helpful in understanding the distribution, transport and fate of lindane in soils and sediments.

scholarly journals Sorption and Desorption of Vanadate, Arsenate and Chromate by Two Volcanic Soils of Equatorial Africa

Soil Systems ◽  
2021 ◽  
Vol 5 (2) ◽  
pp. 22
Author(s):  
Sara Gonzalez-Rodriguez ◽  
Maria Luisa Fernandez-Marcos
Keyword(s):  
Laboratory Experiments ◽  
Sorption Isotherms ◽  
Soil Samples ◽  
Mineral Surfaces ◽  
Volcanic Soils ◽  
Iron Species ◽  
Freundlich Model ◽  
Equatorial Africa ◽  
Relevant Role ◽  
Icp Mass Spectrometry

Sorption of oxyanions by soils and mineral surfaces is of interest due to their role as nutrients or pollutants. Volcanic soils are variable charge soils, rich in active forms of aluminum and iron, and capable of sorbing anions. Sorption and desorption of vanadate, arsenate, and chromate by two African andosols was studied in laboratory experiments. Sorption isotherms were determined by equilibrating at 293 K soil samples with oxyanion solutions of concentrations between 0 and 100 mg L−1 V, As, or Cr, equivalent to 0−2.0 mmol V L−1, 0−1.3 mmol As L−1, and 0−1.9 mmol Cr L−1, in NaNO3; V, As, or Cr were determined by ICP-mass spectrometry in the equilibrium solution. After sorption, the soil samples were equilibrated with 0.02 M NaNO3 to study desorption. The isotherms were adjusted to mathematical models. After desorption with NaNO3, desorption experiments were carried out with a 1 mM phosphate. The sorption of vanadate and arsenate was greater than 90% of the amount added, while the chromate sorption was much lower (19–97%). The sorption by the Silandic Andosol is attributed to non-crystalline Fe and Al, while in the Vitric Andosol, crystalline iron species play a relevant role. The V and Cr sorption isotherms fitted to the Freundlich model, while the As sorption isotherms conformed to the Temkin model. For the highest concentrations of oxyanions in the equilibrating solution, the sorbed concentrations were 37–38 mmol V kg−1, 25 mmol As kg−1, and 7.2–8.8 mmol Cr kg−1. The desorption was low for V and As and high for Cr. The comparison of the sorption and desorption isotherms reveals a pronounced hysteresis for V in both andosols and for Cr in the Silandic Andosol. Phosphate induced almost no V desorption, moderate As desorption, and considerable Cr desorption.

Sorption of radionuclides to a cementitious backfill material under near-field conditions

2012 ◽  
Vol 76 (8) ◽  
pp. 3401-3410 ◽  
Author(s):  
M. Felipe-Sotelo ◽  
J. Hinchliff ◽  
N. Evans ◽  
P. Warwick ◽  
D. Read
Keyword(s):  
Organic Compounds ◽  
Degradation Products ◽  
Cellulose Degradation ◽  
Near Field ◽  
Organic Ligand ◽  
Sorption Isotherms ◽  
Field Conditions ◽  
Sorption Behaviour ◽  
Backfill Material ◽  
Order Of Magnitude

AbstractThe sorption behaviour of I−, Cs+, Ni2+, Eu3+, Th4+ and UO2+2on NRVB (Nirex reference vault backfill) a possible vault backfill, at pH 12.8 was studied. Sorption isotherms generated were compared to results obtained in the presence of cellulose degradation products (CDP). Whereas Cs was not affected by the presence of the organic compounds, a notable reduction in the sorption of Th and Eu to cement was observed. The results also indicated limited removal of Ni from solution (with or without an organic ligand) by sorption, the concentration in solution seemingly being determined solely by solubility processes. In the case of uranium, the presence of CDP increased the sorption to cement by almost one order of magnitude. Further studies into the uptake of CDP by cement are being undertaken to identify the mechanism(s) responsible.

Numerical Modelling of the Heat and Mass Transfer in a Channel with Hygroscopic Walls

2008 ◽  
Vol 273-276 ◽  
pp. 782-788 ◽  
Author(s):  
C.R. Ruivo ◽  
J.J. Costa ◽  
A.R. Figueiredo
Keyword(s):  
Mass Transfer ◽  
Porous Medium ◽  
Numerical Modelling ◽  
Heat And Mass Transfer ◽  
Sorption Isotherms ◽  
Physical Modelling ◽  
Desorption Process ◽  
Strongly Coupled ◽  
Two Phases ◽  
Adsorption Desorption

In this paper the numerical modelling of the behaviour of a channel of a hygroscopic compact matrix is presented. The heat and mass transfer phenomena occurring in the porous medium and within the airflow are strongly coupled, and some properties of the airflow and of the desiccant medium exhibit important changes during the sorption/desorption processes. The adopted physical modelling takes into account the gas side and solid side resistances to heat and mass transfer, as well as the simultaneous heat and mass transfer together with the water adsorption/desorption process in the wall domain. Two phases co-exist in equilibrium inside the desiccant porous medium, the equilibrium being characterized by sorption isotherms. The airflow is treated as a bulk flow, the interaction with the wall being evaluated by using appropriated convective coefficients. The model is used to perform simulations considering two distinct values of the channel wall thickness and different lengths of the channel. The results of the modelling lead to a good understanding of the relationship between the characteristics of the sorption processes and the behaviour of hygroscopic matrices, and provide guidelines for the wheel optimization, namely of the duration of the adsorption and desorption periods occurring in each hygroscopic channel.

Land use effects on sorption of pesticides and their metabolites in sandy soils. I. Fenamiphos and two metabolites, fenamiphos sulfoxide and fenamiphos sulfone, and fenarimol and azinphos methyl

Soil Research ◽  
2003 ◽  
Vol 41 (5) ◽  
pp. 847 ◽  
Author(s):  
D. P. Oliver ◽  
R. S. Kookana ◽  
R. B. Salama
Keyword(s):  
Land Use ◽  
Sorption Isotherms ◽  
Strong Relationship ◽  
Native Vegetation ◽  
Limited Information ◽  
Sorption Behaviour ◽  
Complex Interactions ◽  
Azinphos Methyl ◽  
Kd Values ◽  
Land Use Effects

There is very limited information about the effect of land use on sorption behaviour of organic chemicals. It has been documented that clearing natural vegetation and cropping soil typically decreases the original organic carbon (OC) content of soil. Because OC is one of the major parameters controlling pesticide sorption, the effects of land use on the sorption behaviour of fenamiphos and its 2 main metabolites, fenamiphos sulfone (f. sulfone) and fenamiphos sulfoxide (f. sulfoxide), together with fenarimol and azinphos methyl were investigated. Based on sorption isotherms for a subset of soils, using a range of concentrations (2.5, 5.0, 7.5, and 10 mg/L), the use of a single concentration (2 mg/L) was considered adequate to determine sorption coefficients. Generally the Kd values for fenamiphos were significantly (P�<�0.005) higher than those of its 2 metabolites. The sorption coefficients decreased in the order: fenamiphos >> f. sulfone ≥� f. sulfoxide. As both metabolites can apparently move more easily through soil than fenamiphos, they would pose a greater risk to groundwater contamination. For all compounds, only weak relationships were determined between Kd and pH or %silt + clay. Similarly, the relationship between Kd and %OC was poor, when data from all soils were combined for analysis. However, a strong relationship was obtained between sorption coefficients and %OC for fenamiphos in market garden soils (r2 = 0.76***). This was also the case for azinphos methyl and fenarimol, particularly in soils under native vegetation (r2�=�0.71 and 0.73***, respectively). At a given OC content, the soils under Banksia bush generally showed greater sorption than those under market gardens. This effect became more pronounced with increasing OC content, suggesting that the nature and composition of the OC in soils under native vegetation are likely to be different from that in cultivated soils. Clearly the OC content is not an adequate parameter describing the complex interactions between pesticides and organic matter.

scholarly journals Adsorption of Cr(VI), Pb(II) Ions and Methylene Blue Dye from Aqueous Solution using Pristine and Modified Coral Limestone

2020 ◽  
Vol 32 (10) ◽  
pp. 2624-2632
Author(s):  
C.S. Nkutha ◽  
N.D. Shooto ◽  
E.B. Naidoo
Keyword(s):  
Aqueous Solution ◽  
Methylene Blue ◽  
Freundlich Isotherm ◽  
Blue Dye ◽  
Methylene Blue Dye ◽  
Sorption Behaviour ◽  
Freundlich Model ◽  
Experimental Parameters ◽  
Acid And Base ◽  
Modified Adsorbents

This work reports the feasibility of using pristine and chemically modified coral limestones by acid and base. Their potential adsorptive capabilities is probed by treatment of toxic Cr(VI), Pb(II) ions and methylene blue in aqueous solution under different experimental parameters by batch method. Parameters such as agitation time, concentration, temperature and pH were varied to understand the sorption behaviour of the adsorbents in each case. The adsorbents were characterized by SEM, XRD and FTIR. Morphological analysis by SEM micrographs show that the surface of all adsorbents was irregular in nature. XRD spectra confirmed the orthorhombic structure of aragonite in the pristine coral limestones (PCL), acid modified coral limestones (ACL) and base modified coral limestones (BCL). FTIR results affirmed the presence of (CO3 2-) and (-C=O) groups of the carbonate ions and Ca-O attachment to the surface of PCL and removal of CaCO3 characteristic peaks in ACL and BCL. However, in the modified adsorbents shifting of Ca-O peaks occurred. The recorded maximum adsorption capacities of PCL, ACL and BCL for Cr(VI) ions were 69.42, 65.04, 64.88 mg/g, Pb(II) ions 39.36, 74.11, 78.34 mg/g and methylene blue 37.24, 46.28, 46.39 mg/g, respectively. The uptake of Pb(II), Cr(VI) ions, methylene blue onto PCL fitted Freundlich model. Also the uptake of Cr(VI) ions and methylene blue onto ACL and BCL fitted Freundlich isotherm. However, uptake of Pb(II) ions onto both ACL and BCL fitted Langmuir isotherm. The data revealed that the adsorption of Pb(II) ions onto PCL and ACL and methylene blue dye onto PCL was exothermic. Whilst the adsorption of Cr(VI) ions onto PCL, ACL and BCL and methylene blue dye onto ACL and BCL were endothermic in nature, hence increasing the temperature would enhance the uptake of Pb(II) ions onto BCL, Cr(VI) ions onto ACL and BCL and methylene blue onto ACL and BCL. The obtained (ΔGº) values at all studied temperatures for the adsorption of Pb(II), Cr(VI) ions and methylene blue onto PLC, ACL and BCL indicated a spontaneous process.

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