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

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.

2004 ◽  
Vol 4 (5-6) ◽  
pp. 57-64 ◽  
Author(s):  
D. Schippers ◽  
M. Kooi ◽  
P. Sjoerdsma ◽  
F. de Bruijn

In the past year Vitens, The Netherlands' largest water supply company, and Witteveen+Bos, have prepared the preliminary, basic and detailed design for a full-scale ion exchange plant reducing colour in drinking water to a value of less than 10 mg/l PtCo. Current pilot study shows that the results are even better than expected. The plant will be built in 2004 and start-up is scheduled for mid 2005. The introduction of ion exchange at WTP (Water Treatment Plant) Oldeholtpade is part of a larger project, also including softening in pellet reactors, preceded by counter-current aeration and renovation of the existing treatment plant. The colour content present in groundwater is caused by peat layers. In contrast with conventional ion exchange processes, previous pilot studies showed that the exchange capacity of the resin for organics is much larger than expected. The excellent results can be explained by assuming the simultaneous occurrence of adsorption and ion exchange processes on the resin. It can be concluded that optimising operating conditions, such as higher exchange capacity (as KMnO4/liter resin), higher superficial velocity, shorter contact time and longer filter run cycle clearly affect resin volume as well as the required amount of regenerant. Vitens has started additional experiments at WTP Spannenburg to confirm the innovative design parameters. Aim of the research is the relation between adsorption and ion exchange during filtration, in order to clarify the achieved results. Furthermore the relationship between the specific water type (characterisation of organic compounds) and the operational results of ion exchange will be studied. In order to minimise the waste regenerant, treatment towards recycling is studied by dead end nanofiltration. With nanofiltration it is possible to concentrate the waste stream to a maximum of 10% of the original waste stream. The recovered regenerant can be recycled for regeneration of the resin.


Clay Minerals ◽  
2013 ◽  
Vol 48 (2) ◽  
pp. 167-184 ◽  
Author(s):  
C. Watson ◽  
D. Savage ◽  
J. Wilson ◽  
S. Benbow ◽  
C. Walker ◽  
...  

AbstractIn the post-closure period of a geological disposal facility for radioactive waste, leaching of cement components is likely to give rise to an alkaline plume which will be in chemical disequilibrium with the host rock (which is clay in some concepts) and other engineered barrier system materials used in the facility, such as bentonite. An industrial analogue for cement-clay interaction can be found at Tournemire, southern France, where boreholes filled with concrete and cement remained in contact with the natural mudstone for 15–20 years. The boreholes have been overcored, extracted and mineralogical characterization has been performed. In this study, a reactive-transport model of the Tournemire system has been set up using the general-purpose modelling tool QPAC. Previous modelling work has been built upon by using the most up-to-date data and modelling techniques, and by adding both ion exchange and surface complexation processes in the mudstone. The main features observed at Tournemire were replicated by the model, including porosity variations and precipitation of carbonates, K-feldspar, ettringite and calcite. It was found that ion exchange needed to be included in order for C-S-H minerals to precipitate in the mudstone, providing a better match with the mineralogical characterization. The additional inclusion of surface complexation, however, led to limited calcite growth at the concrete-mudstone interface unlike samples taken from the Tournemire site that have a visible line of crusty carbonates along the interface.


2014 ◽  
Vol 16 (2) ◽  
pp. 69-73
Author(s):  
Sebastian Drużyński ◽  
Krzysztof Mazurek ◽  
Katarzyna Białowicz

Abstract In the studies on the recovery of vanadium from vanadium catalyst extracts, three types of polymer strongly acidic ion exchangers were used. The ion exchange resins differed in terms of granularity and their ion exchange capacity. As a result, breakthrough curves were made for three main components of the test extract, i.e.: ions of vanadium, iron and potassium. On this basis the optimum conditions for the removal of iron ions from the solution were defined and the technological concept of the process in the semi-technical scale was proposed.


Membranes ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 114 ◽  
Author(s):  
Bdiri ◽  
Bensghaier ◽  
Chaabane ◽  
Kozmai ◽  
Baklouti ◽  
...  

The use of enzymatic agents as biological solutions for cleaning ion-exchange membranes fouled by organic compounds during electrodialysis (ED) treatments in the food industry could be an interesting alternative to chemical cleanings implemented at an industrial scale. This paper is focused on testing the cleaning efficiency of three enzyme classes (β-glucanase, protease, and polyphenol oxidase) chosen for their specific actions on polysaccharides, proteins, and phenolic compounds, respectively, fouled on a homogeneous cation-exchange membrane (referred CMX-Sb) used for tartaric stabilization of red wine by ED in industry. First, enzymatic cleaning tests were performed using each enzyme solution separately with two different concentrations (0.1 and 1.0 g/L) at different incubation temperatures (30, 35, 40, 45, and 50 °C). The evolution of membrane parameters (electrical conductivity, ion-exchange capacity, and contact angle) was determined to estimate the efficiency of the membrane′s principal action as well as its side activities. Based on these tests, we determined the optimal operating conditions for optimal recovery of the studied characteristics. Then, cleaning with three successive enzyme solutions or the use of two enzymes simultaneously in an enzyme mixture were tested taking into account the optimal conditions of their enzymatic activity (concentration, temperatures, and pH). This study led to significant results, indicating effective external and internal cleaning by the studied enzymes (a recovery of at least 25% of the electrical conductivity, 14% of the ion-exchange capacity, and 12% of the contact angle), and demonstrated the presence of possible enzyme combinations for the enhancement of the global cleaning efficiency or reducing cleaning durations. These results prove, for the first time, the applicability of enzymatic cleanings to membranes, the inertia of their action towards polymer matrix to the extent that the choice of enzymes is specific to the fouling substrates.


2020 ◽  
Author(s):  
Shany Ben Moshe ◽  
Pauline Kessouri ◽  
Dana Erlich ◽  
Alex Furman

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.


1992 ◽  
Vol 25 (1) ◽  
pp. 133-138 ◽  
Author(s):  
E. Maliou ◽  
M. Malamis ◽  
P. O. Sakellarides

The ion exchange properties of the zeolites can be used to remove certain ions from the effluents. In this work a natural clinoptilolite has been examined systematically in order to evaluate whether this low cost mineral can be employed for the removal of the metals lead and cadmium which are very toxic, even at very low concentrations. Studies were performed under various conditions such as presence of different cations (Pb, Cd, Na), zeolite grain size, solution temperature. The results obtained indicate that the size of the zeolite does not affect the actual metal uptake at the equilibrium point, but the metal removal is greatly affected when the contact of the solid/liquid phases is short, a very essential parameter for the waste water treatment. For a short contact time the metal quantities removed using small grain size is nearly doubled. The same pattern is followed at higher temperatures, though a slight increase is observed for both zeolite grain sizes and both metals, lead and cadmium. At equilibrium half of the theoretical exchange capacity of the zeolite is used, approximately 1.4 meq/g for lead and 1.1 meq/g for cadmium. The kinetic curves show very clearly the selectivity of the zeolite for the Pb ions but also significant amounts of cadmium are removed as well.


2021 ◽  
Vol 25 (6) ◽  
pp. 3041-3052
Author(s):  
Shany Ben Moshe ◽  
Pauline Kessouri ◽  
Dana Erlich ◽  
Alex Furman

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.


1997 ◽  
Vol 506 ◽  
Author(s):  
F. J. Pearson ◽  
H. N. Waber ◽  
A. Scholtis

ABSTRACTThe chemical evolution of groundwater in the Palfris marl at Wellenberg has been simulated using a reactive transport model. The results were tested against the chemical and stable carbon isotopic composition of water samples from exploratory boreholes. Water chemistry is constrained by mineral and cation exchange equilibria. To reproduce measured CO2(tot) and δ3C values requires H+ ion exchange. Matching measured ratios between Cl– and other dissolved constituents constrains the relative amounts of reacting water and rock to porosities between I and 10%. NaHCO3 waters sampled from the Palfris are formed by replacement of the initial Na-Cl water by one to five pore volumes of infiltrating Ca-HCO3 recharge water. To entirely exhaust the exchange capacity of the formation so that Ca-HCO3 water persists requires several hundred to several thousand pore volumes of flow. The agreement between model results and measured water chemistry demonstrates a quantitative understanding of the geochemical processes controlling the chemistry of water naturally present in the Palfris marl. These processes will also determine the behaviour of material that might emanate from a repository. In addition, the modelling provides water flow information of use in testing groundwater flow models.


2020 ◽  
Vol 33 (1) ◽  
pp. 47-57
Author(s):  
Anushree Saha ◽  
Manas Kanti Deb ◽  
Mithlesh Mahilang ◽  
Shubhra Sinha

Ion exchange resins (IERs) are solid poly-electrolytes which have both sorption and exchange capacity of several organic compounds. They have the power to separate ionic and non-ionic substances with the surrounding medium. The drug materials or substances are adsorbed on resin, which is commonly known as resinate, these features of IERs have useful applications in pharmaceutical formation (i.e., taste masking, stability and solubility enhancement, etc.) and major applications in drug delivery (i.e., oral, nasal, ophthalmic, transdarmal drug delivery). IE principles have been exploited in the investigation of numerous drug industry problems for many years. Synthetic IERs have been extensively employed in pharmacy and medicine, especially for taste masking or controlled release of drugs and have been expansively studied in the development of novel drug delivery systems and other biomedical applications. In this review, the fascinating IERs involving ion exchange processes in pharmaceutical and clinical applications and also their recent advanced uses have been discussed.


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