[en] Erbium(III) ion imprinted polymer particles were synthesized by preparing ternary complex of erbium imprint ion with 5,7-dichloroquinoline-8-ol (DCQ) and 4-vinylpyridine (VP) and then thermally copolymerizing with methyl methacrylate (functional monomer) and ethylene glycol dimethacrylate (cross linking monomer) in the presence of 2-methoxy ethanol (porogen) and 2,2'-azobisisobutyronitrile (initiator). The imprint ion was removed by stirring the above particles with 50% (v/v) HCl to obtain leached IIP particles. Control polymer (CP) particles were similarly prepared without imprint ion. CP and unleached and leached IIP particles were characterized by spectral, thermal, microanalysis and nitrogen adsorption studies. The preconcentration and selectivity studies for erbium and other selected lanthanides were carried out with leached CP and IIP particles. The preconcentration of 2.0-250 μg of erbium(III) present in 250 ml of solution was possible with as low as 50 mg of IIP particles in the pH range 7.3-7.8. Seven replicate determinations of 25 μg of erbium(III) present in 250 ml of solution gave a mean absorbance of 0.148 with a relative standard deviation of 2.5%. The detection limit corresponding to three times the standard deviation of the blank was found to be 2 μg/250 ml

No abstract available

[en] The delivered intensity from neutron sources plays a major role in the applicability of neutron techniques. This is particularly true when the application requires mono-energetic neutron beams. Development of such neutron sources depends on two main factors; i) the output ion beam current from the accelerator and, ii) the design of the target system for generating neutrons. The design of an intense monoenergetic neutron source reported in this paper is based on a radio-frequency quadrupole deuteron linac system, coupled to a novel high pressure differentially pumped deuterium gas target. The operation of a working system, capable of generating in excess of 10¹⁰ neutrons per second is reported, along with examples of diverse applications. Also discussed are proposed improvements to the design, such that in excess of 10¹² neutron per second will be generated. (author)

[en] Independent verification of environmental samples in South Africa is mainly restricted to the regulation of a nuclear power plant, research reactor and facilities associated with NORM. Over the years, the NNR did not have the in-house capability in this area and relied on the services of one of its license holder’s laboratory, which is not a desired situation considering the need for regulatory independence. In addition, challenges in turnaround times due to the facility being a commercial entity servicing other facilities as well, contributed to delays in regulatory decision-making. The regulator took a decision to establish an independent verification laboratory, through expert support via a local Technical Support Organization (TSO). The establishment of the radio-analytical laboratory with the TSO resulted in regulatory independence and in establishing expertise within the regulator to do analyses of many other radionuclides not covered previously. As this was the first experience by the regulator to enlist a TSO in the establishment of the laboratory, (which included the following tasks: designing of the laboratory; procurement and commissioning of instruments; capacity building; development of quality management systems; and development of procedures and methods) many challenges and difficulties were experienced during the process. The experiences are detailed in this paper that covers the cost of project management, procurement delays, and limited skills within the country and in the regulator to cover specialized knowledge pertaining to analytical methodologies. Another major challenge involved on the job training without the instruments being installed and commissioned. (author)

[en] Erbium(III) ion imprinted polymer (IIP) particles were synthesized by preparing erbium(III)-5,7-dichloroquinoline-8-ol-4-vinylpyridine prepolymer complex and then copolymerizing via γ-irradiation with different functional and crosslinking monomer combinations, viz. styrene-divinyl benzene, 2-hydroxyethyl methacrylate (HEMA)-ethylene glycoldimethacrylate (EGDMA), methyl methacrylate (MMA)-EGDMA. The erbium(III) imprint ion was removed by stirring the above particles with 6.0 mol l^-1 HCl to obtain leached IIP particles. Control polymer (CP) particles were prepared without imprint ion. Again, CP, unleached and leached IIP particles were characterized by XRD, UV-vis spectrophotometric, pore size, SEM, and swelling ratio studies. The preconcentration of traces of erbium(III) during rebinding with leached IIP particles was studied as a function of pH, weight of polymer material, preconcentration and elution times, eluent concentration and volume, and aqueous phase volume. These studies indicate that as low as 2 μg of erbium(III) present in 500 ml can be preconcentrated into 20 ml of 1.0 mol l^-1 HCl, and thus providing an enrichment factor of ∼25. Furthermore, the present study indicates that styrene-divinyl benzene-based IIP could be a better choice for the separation of erbium(III) from yttrium(III), dysprosium(III), holmium(III), and thulium(III) compared to HEMA-EGDMA and MMA-EGDMA-based IIPs

[en] Ion-selective electrode (ISE) was designed by dispersing the dysprosium(III) IIP particles in 2-nitrophenyloctyl ether plasticizer and then embedded in polyvinyl chloride matrix. The ISE shows a Nernstian response for dysprosium(III) over a wide concentration range (8.0 x 10^-6 to 1.0 x 10^-1 M) with a slope of 21.7 mV per decade. The limit of detection was 2 x 10^-6 M. This sensor has a very fast response time (∼10 s) and offers high selectivity compared to conventional chemical sensors towards dysprosium(III) with respect to several alkali, alkaline earth and transition metal ions as the selectivity is 10-100-fold better. The sensor was used for determination of dysprosium(III) ions by potentiometric (EDTA) titration and has been successfully demonstrated for the determination of fluoride in mouth wash solution

[en] In view of the extreme toxicity of uranium and consequent stringent limits fixed by WHO and various national governments, it is essential to monitor the uranium content in the environment which is at ultratrace levels. Conventional ionophore based ion selective electrodes, barring a few, have limitations in terms of sensitivity and selectivity for the above mentioned purpose. We now propose an ion imprinted polymer (biomimetic) based potentiometric sensor by dispersing the uranyl ion imprinted polymer particles in 2-nitrophenyloctyl ether (plasticizer), which is embedded in polyvinyl chloride matrix. The sensor responds to uranyl ion over a wide concentration range of 2.0 x 10^-8 to 1.0 x 10^-2 M. The limit of detection was 2.0 x 10^-8 M. It showed a good selectivity for uranyl ion over alkali, alkaline earth, transition and heavy metal cations. The sensor is successfully tested for the monitoring of toxic uranium in tap and sea water samples