scholarly journals Geophysically based analysis of breakthrough curves and ion exchange processes in soil

2021 ◽  
Vol 25 (6) ◽  
pp. 3041-3052
Author(s):  
Shany Ben Moshe ◽  
Pauline Kessouri ◽  
Dana Erlich ◽  
Alex Furman
Keyword(s):  
Ion Exchange ◽  
Soil Column ◽  
Breakthrough Curves ◽  
Soil Profiles ◽  
The Real ◽  
Water Composition ◽  
Exchange Processes ◽  
Heterogeneous Soil ◽  
Quantitative Examination ◽  
Transport Patterns

Abstract. Breakthrough curves (BTCs) are a valuable tool for qualitative and quantitative examination of transport patterns in porous media. Although breakthrough (BT) experiments are simple, they often require extensive sampling and multi-component chemical analysis. In this work, we examine spectral induced polarization (SIP) signals measured along a soil column during BT experiments in homogeneous and heterogeneous soil profiles. Soil profiles were equilibrated with an NaCl background solution, and then a constant flow of either CaCl2 or ZnCl2 solution was applied. The SIP signature was recorded, and complementary ion analysis was performed on the collected outflow samples. Our results confirm that changes to the pore-water composition, ion exchange processes and profile heterogeneity are detectable by SIP: the real part of the SIP-based BTCs clearly indicated the BT of the non-reactive ions as well as the retarded BT of cations. The imaginary part of the SIP-based curves changed in response to the alteration of ion mobility around the electrical double layer (EDL) and indicated the initiation and the termination of the cation exchange reaction. Finally, both the real and imaginary components of the complex conductivity changed in response to the presence of a coarser textured layer in the heterogeneous profile.

scholarly journals Geophysically-based analysis of BTCs and ion exchange processes in soil

2020 ◽  
Author(s):  
Shany Ben Moshe ◽  
Pauline Kessouri ◽  
Dana Erlich ◽  
Alex Furman
Keyword(s):  
Ion Exchange ◽  
Soil Column ◽  
Breakthrough Curves ◽  
Soil Profiles ◽  
The Real ◽  
Water Composition ◽  
Exchange Processes ◽  
Heterogeneous Soil ◽  
Quantitative Examination ◽  
Transport Patterns

Abstract. Breakthrough curves (BTCs) are a valuable tool for qualitative and quantitative examination of transport patterns in porous media. Although breakthrough (BT) experiments are simple, they often require extensive sampling and multi-component chemical analysis. In this work, we examine spectral induced polarization (SIP) signals measured along a soil column during a BT experiment in a homogeneous and heterogeneous soil profiles. Soil profiles were equilibrated with an NaCl background solution and then a constant flow of CaCl2 solution was applied. SIP signature was recorded, and complementary ion analysis was performed on the collected outflow samples. Our results confirm that changes to the pore-water composition, ion exchange processes and profile heterogeneity are detectable by SIP: the real part of the conductivity-based BTCs clearly indicated the BT of the non-reactive ions as well as the retarded BT of Ca2+. The imaginary part of the conductivity-based curves reacted to the changes in ion mobility around the electrical double layer (EDL) and indicated the initiation and the termination of the Na+–Ca2+ exchange reaction. Finally, both the real and imaginary components of the complex conductivity reacted to the presence of a coarser textured layer in the heterogeneous profile.

scholarly journals Modeling of Ion Exchange Processes to Optimize Metal Removal from Complex Mine Water Matrices

Water ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3109
Author(s):  
Angela Isabel Pedregal Montes ◽  
Janith Abeywickrama ◽  
Nils Hoth ◽  
Marlies Grimmer ◽  
Carsten Drebenstedt
Keyword(s):  
Ion Exchange ◽  
Mine Water ◽  
Reactive Transport ◽  
Metal Removal ◽  
Transport Model ◽  
Breakthrough Curves ◽  
Exchange Capacity ◽  
Operating Conditions ◽  
Mine Waters ◽  
Exchange Processes

The modeling of ion exchange processes could significantly enhance their applicability in mine water treatment, as the modern synthetic resins give unique advantages for the removal of metals. Accurate modeling improves the predictability of the process, minimizing the time and costs involved in laboratory column testing. However, to date, the development and boundary conditions of such ion exchange systems with complex mine waters are rarely studied and poorly understood. A representative ion exchange model requires the definition of accurate parameters and coefficients. Therefore, theoretical coefficients estimated from natural exchange materials that are available in geochemical databases often need to be modified. A 1D reactive transport model was developed based on PhreeqC code, using three case scenarios of synthetic mine waters and varying the operating conditions. The first approach was defined with default exchange coefficients from the phreeqc.dat database to identify and study the main parameters and coefficients that govern the model: cation exchange capacity, exchange coefficients, and activity coefficients. Then, these values were adjusted through iterative calibration until a good approximation between experimental and simulation breakthrough curves was achieved. This study proposes a suitable methodology and challenges for modeling the removal of metals from complex mine waters using synthetic ion exchange resins.

scholarly journals Rapid column experiments to study replacement of exchangeable cations in soil samples.

1989 ◽  
Vol 37 (3) ◽  
pp. 213-225
Author(s):  
S. El-Guindy ◽  
J. Harmsen
Keyword(s):  
High Performance ◽  
Soil Column ◽  
Breakthrough Curves ◽  
Soil Samples ◽  
Exchangeable Cations ◽  
High Flow ◽  
Model Calculations ◽  
Small Column ◽  
Exchange Processes ◽  
Leaching Solution

A new and rapid soil column technique is described that can verify model calculations on transport and exchange of cations in soil, using equipment for high-performance liquid chromatography (HPLC). Breakthrough curves of cations are presented and compared with results of a model that simulates transport and exchange processes in a soil column. The small column dimensions and the high flow rate allow leaching of individual columns to be completed within one day. Equiulibrium is established almost instantaneously between the leaching solution and the soil in the column. (Abstract retrieved from CAB Abstracts by CABI’s permission)

scholarly journals Theoretical Modelling of Ion Exchange Processes in Glass: Advances and Challenges

2021 ◽  
Vol 11 (11) ◽  
pp. 5070
Author(s):  
Xesús Prieto-Blanco ◽  
Carlos Montero-Orille
Keyword(s):  
Ion Exchange ◽  
Diffusion Coefficients ◽  
Molten Salts ◽  
Theoretical Modelling ◽  
Copper Films ◽  
Theoretical Frameworks ◽  
Self Diffusion ◽  
Exchange Processes ◽  
The One ◽  
Made In

In the last few years, some advances have been made in the theoretical modelling of ion exchange processes in glass. On the one hand, the equations that describe the evolution of the cation concentration were rewritten in a more rigorous manner. This was made into two theoretical frameworks. In the first one, the self-diffusion coefficients were assumed to be constant, whereas, in the second one, a more realistic cation behaviour was considered by taking into account the so-called mixed ion effect. Along with these equations, the boundary conditions for the usual ion exchange processes from molten salts, silver and copper films and metallic cathodes were accordingly established. On the other hand, the modelling of some ion exchange processes that have attracted a great deal of attention in recent years, including glass poling, electro-diffusion of multivalent metals and the formation/dissolution of silver nanoparticles, has been addressed. In such processes, the usual approximations that are made in ion exchange modelling are not always valid. An overview of the progress made and the remaining challenges in the modelling of these unique processes is provided at the end of this review.

Ion-exchange breakthrough curves for single and multi-metal systems using marine macroalgae Pelvetia canaliculata as a natural cation exchanger

2015 ◽  
Vol 269 ◽  
pp. 359-370 ◽  
Author(s):  
Fabíola V. Hackbarth ◽  
Franciélle Girardi ◽  
João C. Santos ◽  
Antônio Augusto U. de Souza ◽  
Rui A.R. Boaventura ◽  
...  
Keyword(s):  
Ion Exchange ◽  
Cation Exchanger ◽  
Breakthrough Curves ◽  
Marine Macroalgae

Ion exchange processes in aqueous-organic media

1969 ◽  
Vol 41 (14) ◽  
pp. 2047-2050 ◽  
Author(s):  
J. L. Pauley ◽  
D. D. Vietti ◽  
C. C. Ou-Yang ◽  
D. A. Wood ◽  
R. D. Sherrill
Keyword(s):  
Ion Exchange ◽  
Organic Media ◽  
Exchange Processes

scholarly journals A Review on the Catalytic Hydrogenation of Bromate in Water Phase

Catalysts ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 365
Author(s):  
Jose Luis Cerrillo ◽  
Antonio Eduardo Palomares
Keyword(s):  
Catalytic Activity ◽  
Ion Exchange ◽  
Reaction Mechanisms ◽  
Catalytic Reduction ◽  
Environmental Concern ◽  
Chemical Reduction ◽  
Catalyst Stability ◽  
Polluted Water ◽  
Water Composition

The presence of bromate in water sources generates environmental concern due to its toxicity for humans. Diverse technologies, like membranes, ion exchange, chemical reduction, etc., can be employed to treat bromate-polluted water but they produce waste that must be treated. An alternative to these technologies can be the catalytic reduction of bromate to bromide using hydrogen as a reducing agent. In this review, we analyze the research published about this catalytic technology. Specifically, we summarize and discuss about the state of knowledge related to (1) the different metals used as catalysts for the reaction; (2) the influence of the support on the catalytic activity; (3) the characterization of the catalysts; (4) the reaction mechanisms; and (5) the influence of the water composition in the catalytic activity and in the catalyst stability. Based on published papers, we analyze the strength and weaknesses of this technique and the possibilities of using this reaction for the treatment of bromate-polluted water as a sustainable process.

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