Ion-exchange technique (IET) for measuring Cu2+, Ni2+ and Zn2+ activities in soils contaminated with metal mixtures

2017 ◽  
Vol 14 (1) ◽  
pp. 55 ◽  
Author(s):  
D. M. Schwertfeger ◽  
W. H. Hendershot
Keyword(s):  
Organic Matter ◽  
Ion Exchange ◽  
Metal Binding ◽  
Mean Squared Error ◽  
Metal Speciation ◽  
Ion Exchange Resin ◽  
Metal Bioavailability ◽  
Soil Extracts ◽  
Metal Mixtures ◽  
Exchange Technique

Environmental contextTerrestrial environments receiving trace metal contaminants are often impacted by more than one metal. This study demonstrates the adaptation of an ion-exchange technique to simultaneously obtain Cu2+, Ni2+ and Zn2+ activities in soil extracts. These measurements can be used to better understand and predict the behaviour and bioavailability of soil metals in metal–mixture contamination scenarios. AbstractReliable estimates of metal speciation are critical for predicting metal bioavailability and the toxicological effects of metal mixtures in the soil environment; however, simultaneous measurements of metal free ion activities in complex matrices pose a challenge. Although speciation models maybe useful, the uncertainty of metal binding to natural organic matter requires that such models be validated with empirical data. In this study, an ion-exchange resin technique (IET) was adapted for the analysis of Cu2+, Ni2+ and Zn2+ in soil extracts. The analysis was performed with three different soil types spiked with single and multiple metal additions to obtain a range of metal concentrations and combinations. Method detection limits of 0.006, 0.04 and 0.05µM for Cu2+, Ni2+ and Zn2+ were achieved. The values obtained by IET were comparable with those estimated by Visual MINTEQ, giving a root mean squared error of 0.21, 0.30 and 0.34 (n=30) for the Cu, Ni and Zn data. The Cu2+ activities obtained by IET were within an order of magnitude of those obtained by a Cu ion-selective electrode, being on average 6-fold greater, with better agreement occurring in samples having lower organic matter contents. The resulting soil metal speciation data revealed that the partitioning of soil Cu to the potentially bioavailable Cu2+ pool differed in the binary mixture with Ni compared with the single-metal Cu treatments. These data can be used to assess metal bioavailability and aid in the interpretation of ecotoxicological effects observed in soils where multiple metals are a concern.

Adsorptive Removal of Natural Organic Matter during Drinking Water Treatment

1999 ◽  
Vol 40 (9) ◽  
pp. 183-190 ◽  
Author(s):  
S. G. J. Heijman ◽  
A. M. van Paassen ◽  
W. G. J. van der Meer ◽  
R. Hopman
Keyword(s):  
Organic Matter ◽  
Ion Exchange ◽  
Natural Organic Matter ◽  
Exchange Resin ◽  
Drinking Water Treatment ◽  
Ion Exchange Resin ◽  
Batch Experiments ◽  
Colour Removal ◽  
Adsorptive Removal ◽  
First Choice

For the removal of DOC (and colour) several treatment steps are suggested. If it is also necessary to remove hardness nanofiltration is probably the first choice. For colour removal without softening a number of adsorbents are suggested in the literature. In order to estimate the costs of these treatment steps a dynamic column model based on batch experiments was used to predict the service time of the columns filled with different adsorbents. Also the (on site) regeneration of the different adsorbents was investigated in batch experiments. Especially the ion exchange resin was very promising. The costs of the treatment of one m3 water with a column filled with an ion exchange resin was estimated for the investigated case at 0.05 Euro.

scholarly journals Assessment of labilities of metal complexes with the dynamic ion exchange technique

2019 ◽  
Vol 16 (3) ◽  
pp. 151
Author(s):  
Federico Quattrini ◽  
Josep Galceran ◽  
Carlos Rey-Castro ◽  
Jaume Puy ◽  
Claude Fortin
Keyword(s):  
Ion Exchange ◽  
Natural Waters ◽  
Breakthrough Curves ◽  
Short Exposure ◽  
Metal Bioavailability ◽  
Operation Conditions ◽  
The Impact ◽  
Free Metal ◽  
Metal Ligand ◽  
Exchange Technique

Environmental contextIn natural waters, the impact of metals on biota is modulated by their binding with ligands. Ion-exchange techniques can provide information about metal-ligand complexes in solution, which can be linked to metal bioavailability in natural waters. We investigate modelling approaches to interpreting data from ion-exchange experiments to help elucidate the contribution of a particular complex to the overall metal uptake. AbstractThe dynamic ion exchange technique (DIET) is proposed to provide speciation information, which can be used to establish links with metal bioavailability in natural waters. The experimental setup consists of a few milligrams of a sulfonic acid type ion exchange resin packed in a plastic microcolumn that is coupled to a peristaltic pump for a sample to interact with the resin which is subsequently eluted. The evolution of both the accumulated number of moles in the resin and the concentration of the effluent can provide information on the dissociation of different metal-ligand complexes when compared with the transport properties. This information can be converted into the lability degree of a given complex or the DIET concentration cDIET, which accounts for the labile fraction contributing to the metal accumulation by the resin column at the operation conditions. cDIET can be extended to columns containing chelating resins (such as those with Chelex) or to chromatography. A comprehensive modelling of the involved phenomena (such as diffusion, advection, reaction kinetics and electrostatic partitioning) leads to the quantitative interpretation of the accumulation time series (accumulation curves) or effluent evolution (breakthrough curves). Particularly simple analytical expressions can be used for short exposure times, when a (quasi) steady-state is attained. These models have been checked against the results from complexes of Cu and Ni with ligands, such as ethylenediamine, and ethylenediaminetetraacetic, iminodiacetic, glutamic, salicylic, malonic and malic acids, which yield complexes with contrasting charges. Caution is advised when estimating the free metal fraction from DIET measurements, as cDIET and the free metal concentration can be considered to be equal only in the case of extremely inert complexes.

scholarly journals Determination of the free-ion concentration of rare earth elements by an ion-exchange technique: implementation, evaluation and limits

2016 ◽  
Vol 13 (3) ◽  
pp. 478 ◽  
Author(s):  
Sébastien Leguay ◽  
Peter G. C. Campbell ◽  
Claude Fortin
Keyword(s):  
Ion Exchange ◽  
Natural Organic Matter ◽  
Metal Ion ◽  
Exchange Resin ◽  
Ion Exchange Resin ◽  
Ion Concentration ◽  
Free Ion ◽  
Free Metal ◽  
Free Metal Ion ◽  
Exchange Technique

Environmental context The lanthanides are a group of heavy elements (from lanthanum to lutetium) increasingly used in many electronic consumer products and little is known about their environmental mobility and toxicity. In natural systems, these elements will bind to natural organic matter but metal toxicity is usually defined by the free metal ion concentration. Here, we propose a method based on sample equilibration with an ion-exchange resin to measure the free lanthanide ion concentration in the presence of natural organic matter. Abstract An ion-exchange technique that employs a polystyrene sulphonate ion-exchange resin was developed for determining environmentally relevant free-ion concentrations of Ce, Eu, La and Nd. Owing to the high affinity of rare earth elements (REE) for the selected resin, this method requires the addition of an inert salt to increase the concentration of the counter-ions (i.e. cations that are exchanged with REE bound to the resin). The use of a batch equilibration approach to calibrate the resin allowed the implementation of the ion-exchange technique at reasonably low ionic strength (I = 0.1M). Several ligands were used to test the selectivity of the method, which proved to be highly selective for the free metal ion in presence of the tested cationic and anionic complexes (REE–nitrate, REE–malic acid and REE–nitrilotriacetic acid systems) and operational for very low proportions of REE3+, owing to the strong REE–resin interactions. The ion-exchange technique was also implemented to determine [Eu]inorg in the presence of natural humic matter (Suwannee River Humic Acid) and the results were compared with those obtained using equilibrium dialysis and those calculated with chemical equilibrium models. At pH 4.00, the measured [Eu]inorg values were in fairly good agreement with those predicted with the Windermere Humic Aqueous Model and Stockholm Humic Model, whereas the Non-Ideal Competitive Absorption model appeared to underestimate the [Eu]inorg. However, the inorganic europium concentrations were strongly underestimated (4 < [Eu]inorg, IET/[Eu]inorg, calc < 18) with the three prediction models at higher pH (5.3 and 6.2).

Speciation of a lanthanide (Sm) using an ion exchange resin

2016 ◽  
Vol 8 (37) ◽  
pp. 6774-6781 ◽  
Author(s):  
Ildephonse Nduwayezu ◽  
Fatemeh Mostafavirad ◽  
Madjid Hadioui ◽  
Kevin J. Wilkinson
Keyword(s):  
Rare Earth ◽  
Ion Exchange ◽  
Environmental Samples ◽  
Exchange Resin ◽  
Rare Earth Metals ◽  
Ion Exchange Resin ◽  
Exchange Technique ◽  
The Rare Earth

An ion exchange technique has been developed to enable speciation measurements of the rare earth metals in environmental samples.

Importance of the order in enhancing EfOM removal by combination of BAC and MIEX®

2011 ◽  
Vol 64 (11) ◽  
pp. 2325-2332 ◽  
Author(s):  
A. Aryal ◽  
A. Sathasivan
Keyword(s):  
Organic Matter ◽  
Activated Carbon ◽  
Organic Carbon ◽  
Ion Exchange ◽  
Exchange Resin ◽  
Wastewater Reuse ◽  
Ion Exchange Resin ◽  
Wastewater Effluent ◽  
Biological Activated Carbon ◽  
Magnetic Ion

Biological activated carbon (BAC) is operationally a simple treatment which can be employed to remove effluent organic matter (EfOM) from secondary wastewater effluent (SWWE). Unfortunately, BAC removes only a limited amount of dissolved organic carbon (DOC). Thus, maximizing DOC removal from SWWE using BAC is a major concern in wastewater reuse. This study has investigated a hybrid system of BAC and Magnetic Ion Exchange Resin (MIEX®) for the enhanced removal of DOC. Performance of both BAC prior to MIEX® (BAC/MIEX®) and reverse (MIEX®/BAC) combination was evaluated in terms of DOC removal. The BAC/MIEX® showed much better DOC removal. This is because microbial activity in the BAC bed converted MIEX® non-amenable DOC to MIEX® amenable DOC. As a result, BAC/MIEX® combination synergised DOC removal. In addition, BAC was also found to be highly effective in reducing MIEX® dose for a given DOC removal from SWWE.

Removal of algogenic organic matter by magnetic ion exchange resin pre-treatment and its effect on fouling in ultrafiltration

2011 ◽  
Vol 11 (1) ◽  
pp. 15-22 ◽  
Author(s):  
C. Liu ◽  
W. Chen ◽  
V. M. Robert ◽  
Z. G. Han
Keyword(s):  
Organic Matter ◽  
Ion Exchange ◽  
Membrane Fouling ◽  
Exchange Resin ◽  
Ion Exchange Resin ◽  
Major Barrier ◽  
Treated Water ◽  
Fouling Control ◽  
Pre Treatment ◽  
Magnetic Ion

Natural organic matter (NOM) fouling continues to be the major barrier to efficient application of ultrafiltration (UF) in drinking water treatment. Algogenic organic matter (AOM), the main contributor to total NOM levels in raw waters characterised by elevated algae levels, is currently the subject of much investigation. In this study, the effect of AOM on fouling of ultrafiltration and the effectiveness of magnetic ion exchange resin (MIEX®) pre-treatment for AOM removal and membrane fouling control was evaluated. The results showed that, the main species of algae in raw water were Chlorella vulgaris, which accounted for 80% of total algae. AOM was predominantly hydrophilic (50% or more) with a low SUVA (1.7 Lm−1 mg−1). Coagulation alone could not remove AOM effectively (less than 20%), however, when combined with magnetic ion exchange resin pre-treatment, more than 60% of AOM was be removed; pre-treatment followed by coagulation was observed to be very effective in controlling membrane fouling by AOM. The application of magnetic ion exchange resin technology at a bed volume treatment rate (BVTR) of 800 was observed to effectively eliminate fouling of UF membrane. Careful analyses of the molecular weight (MW) distribution of AOM and UV absorbance of treated water revealed that the effectiveness in membrane fouling control was the result of the changes in AOM molecular characteristics in treated water, namely a change in MW due to the preferential removal of high molecular proteins by coagulation and magnetic ion exchange resin pre-treatment. The results demonstrate that magnetic ion exchange resin followed by coagulation might be a new membrane pre-treatment option for UF membrane fouling control.

Sign in / Sign up

Export Citation Format

Share Document