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The chelating exchange resin Chelex 100, with functional group iminodiacetic acid (IDA), was used to remove Cd (II) and Ni (II) from aqueous solutions. Batch elution experiments using Cd (II) and Ni (II) solutions were compared. Experiments were finally performed at different pH values (2.0–7.0), metal ion concentrations (10–500 mg/l), and resin do...
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Abstract: An on-line preconcentration procedure for the determination of heavy metal ions using Flow-injection approach with flame atomic absorption spectroscopy is developed significantly in recent years. This review focuses on chelating resins based on Amberlite XAD resins which have been used in Flow Injection analysis since 1996.The factors lik...
A sensitive, simple method for the determination of amounts of mixture of Hg2+and Cd2+ by
spectrophotometry was described based on the formation of the Hg2+- Cd2+- PAN complex in
water media. Optimal conditions such as reagent amounts, and pH for the Hg2+- Cd2+ determination
were reported. It was found that the 2:1 PAN- Hg2+- Cd2+ complex dominate...
The liquid–liquid and liquid-solid extractions of samarium(III) from aqueous nitrate solution using D2EHPA (di-2-ethylhexyl phosphoric acid) and chelating resin “Chelex 100” as extractants is investigated to recover samarium(III) from aqueous solution. The effect of operating parameters, such as time, nitrate ion, aqueous phase acidity, concentrati...
The adsorption of metallic elements on the solid phase chelating resins is probably the most effective separation and preconcentration methods. In this work, portable Solid phase extraction (SPE) was constructed using a commercially available plastic syringe containing certain amount of the Analiq ME-02 chelating resin. The ability of this portable...
The adsorption of metallic elements on the solid phase chelating resins is probably the most effective separation and preconcentration methods. In this work, portable Solid phase extraction (SPE) was constructed using a commercially available plastic syringe containing certain amount of the Analiq ME-02 chelating resin. The ability of this portable...
Citations
... They have cumulative effect and tend to accumulate in the living organisms causing various diseases. Therefore, reduction in the pollutant to an acceptable level is necessary [7,8]. A number of techniques are available for removal of heavy metal ions from aqueous solutions. ...
In this work, the adsorption behavior of cadmium and nickel was studied using natural dolomite powder. The adsorption experiments were carried out to investigate adsorption parameters including metal ions concentration, solution pH, contact time, and temperature using a batch technique. The equilibrium adsorption isotherm data of the metal ions adsorption were best described by Freundlich, Langmuir, and Dubinin–Radushkevich isotherm models. The adsorption capacity was obtained 1.46 and 1.70 mg/g for cadmium and nickel, respectively. Kinetic studies revealed that the initial uptake was rapid and equilibrium was established in, 120 and 105 min for Cd(II) and Ni(II), respectively. The results showed that the data followed the pseudo-second-order reaction. Thermodynamic analysis showed that the adsorption of the metal ions on dolomite is feasible and exothermic. The mean free energy values obtained using the Dubinin–Radushkevich model for the ions showed that the adsorption of nickel and cadmium ions onto dolomite occurs via a physical process for all the temperatures.
... The World Health Organization (WHO) recommended maximum permissible limit of Cd(II) in drinking water to be 0.005 mg/L[44]. Removal of cadmium from water has been the objective of different works[45][46][47][48][49][50][51][52]. When different heavy metals are present together, their simultaneous removal from aqueous solution or wastewater becomes more complicated because there are effects of each metal on others. ...
In this study, the sawdust was used as an abundant and inexpensive material for the
removal of two heavy metals simultaneously from an aqueous solution. In order to evaluate
the adsorbent potential of the sawdust, the effects of many operating parameters were studied.
The metals considered were zinc and cadmium. The experiments were organized according
to a well defined window of a statistical design of experiments. Starting from a large
number of operating parameters (type, source, size and quantity of sawdust, temperature,
pH, contact time, stirring speed, initial concentrations of cadmium, zinc and salt), a Plackett–
Burman design was used to identify the most influential factors on the elimination performance
of zinc and cadmium simultaneously with a minimum number of experiments. Effects
of these factors were deduced from an interesting statistical treatment of experimental
responses. For Zn sorption, the most important factors are mass of sawdust, initial concentration
of zinc and time; while for Cd sorption, the most important factors are initial concentrations
of zinc and cadmium, pH, mass, type and size of sawdust. The presence of cadmium
decreased the removal of zinc considerably and the inverse did not happen. These effects
were more remarkable for cadmium (sorption varied from 0 to 80%) than for zinc (sorption
varied from 0 to 50%). These results allowed to choose the most important parameters which
could be optimized using another designs of experiments, such as Box Behnken or full factorial,
and response surface methodology to obtain the best performance of metals sorption.
Quantum-chemical calculations of complexation energies of iminodiacetic acid with cations of monovalent and divalent metals were carried out. Energy calculations were estimated by the RHF with 6-31G(d,p) basis, taking the MP2 correlation. The results of the calculations show that of the two electroneutral forms of iminodiacetic acid, the mesoionic form is somewhat more stable. For two single charged anionic forms of iminodiacetic acid, the form with protonated nitrogen is more stable. Only doubly charged anionic form (IDA2–) has the ability to form stable complexes with metals, because all other forms have only two potential coordination centers, as opposed to three in IDA2–. According to the results of the calculation, a scheme of acid-base interaction in aqueous solutions of iminodiacetic acid has been compiled. Two parallel methods for calculating the complexation energies of cations with iminodiacetic acid have been proposed. The obtained values unequivocally indicate that the energy of complexation significantly increases when going from monovalent cations of alkali metals to divalent cations of transition metals. The results of quantum chemical calculations are in good agreement with literature data on the selectivity of sorption of metal cations from aqueous solutions. The performed calculations show that iminodiacetic acid and its derivatives are an effective class of new sorbents capable of selective extraction of heavy metal cations. In the case of the simultaneous presence of different cations in solution, the ligand is able to select cations for binding, and can be used to create a “smart” material.
The stripping voltammetry at HMDE is proposed for Cd and Pb (undesirable ingredients) determination in the natural brine (CCl > 43 g L‐1). Samples with so high salinity have to be significantly diluted. For ICP MS, a 105‐6 times dilution is required, which disqualifies this method. The proposed procedure allows to determine Cd (0.001 µg L‐1) and Pb (0.005 µg L‐1) after only 100 times dilution. The thermal chloride stripping or isolation by Chelex 100 increase the quality of obtained data. The recovery study was performed. The LOQs are below recommendations related to the use of brines in balneology.
Pollution by heavy metal ions in aqueous systems gained researchers attention gradually. Toxic metal ions were always present in the environment and the living organisms could get used to specific concentrations of contaminants with given time, however, sudden concentration rise we are observing can make it impossible for the living organisms to adapt. Many ion removal technologies were developed and optimised over the years to cope with this problem, including chemical precipitation, adsorption, membrane filtration and ion-exchange. Adsorption and ion exchange are processes that employ certain materials, that can be collectively named ion scavengers, to remove ions from aqueous solutions. Some of the scavenger materials are still barely studied, in particular polyampholytes – polymeric zwitterionic materials. This review showcases papers published on toxic metal ion removal by polyampholytes, both commercial and experimental, over last two decades. Many recent publications show promising properties of experimental materials that match or even outperform commercial scavengers. This review was prepared to encourage other researchers to investigate this broad and still not well-studied class of materials especially in context of their ion-scavenging properties. Polyamphytes which may be especially worth the attention and further research have been highlighted as literature studies show that the most unexplored materials in the class of polyamphytes are those containing aminomethylphosphonate, aminomethylsulfonate or hypophosphorous acid group.
