Capture of aqueous radioiodine species by metallated adsorbents from wastestreams of the nuclear power industry : a review

Iodine-129 poses a significant challenge in the drive towards lowering radionuclide emissions from used nuclear fuel recycling operations. Various techniques are employed for capture of gaseous iodine species, but it is also present, mainly as iodide anions, in problematic residual aqueous wastestreams, which have stimulated research interest in technologies for adsorption and retention of the radioiodine. This removal effort requires specialised adsorbents, which use soft metals to create selectivity in the challenging chemical conditions. A review of the literature, at laboratory scale, reveals a number of organic, inorganic and hybrid adsorbent matrices have been investigated for this purpose. They are functionalised principally by Ag metal, but also Bi, Cu and Pb, using numerous synthetic strategies. The iodide capacity of the adsorbents varies from 13 to 430 mg g−1, with ion-exchange resins and titanates displaying the highest maximum uptakes. Kinetics of adsorption are often slow, requiring several days to reach equilibrium, although some ligated metal ion and metal nanoparticle systems can equilibrate in < 1 h. Ag-loaded materials generally exhibit superior selectivity for iodide verses other common anions, but more consideration is required of how these materials would function successfully in industrial operation; specifically their performance in dynamic column experiments and stability of the bound radioiodine in the conversion to final wasteform and subsequent geological storage

Functionality screening to help design effective materials for radioiodine abatement

This paper is part of a growing body of research work looking at the synthesis of an optimal adsorbent for the capture and containment of aqueous radioiodine from nuclear fuel reprocessing waste. 32 metalated commercial ion exchange resins were subjected to a two-tier screening assessment for their capabilities in the uptake of iodide from aqueous solutions. The first stage determined that there was appreciable iodide capacity across the adsorbent range (12–220 mg·g−1). Candidates with loading capacities above 40 mg·g−1 were progressed to the second stage of testing, which was a fractional factorial experimental approach. The different adsorbents were treated as discrete variables and concentrations of iodide, co-contaminants and protons (pH) as continuous variables. This gave rise to a range of extreme conditions, which were representative of the industrial challenges of radioiodine abatement. Results were fitted to linear regression models, both for the whole dataset (R2 = 59%) and for individual materials (R2 = 18–82%). The overall model determined that iodide concentration, nitrate concentration, pH and interactions between these factors had significant influences on the uptake. From these results, the top six materials were selected for project progression, with others discounted due to either poor uptake or noticeable iodide salt precipitation behaviour. These candidates exhibited reasonable iodide uptake in most experimental conditions (average of >20 mg·g−1 hydrated mass), comparing favourably with literature values for metallated adsorbents. Ag-loaded Purolite S914 (thiourea functionality) was the overall best-performing material, although some salt precipitation was observed in basic conditions. Matrix effects not withstanding it is recommended that metalated thiourea, bispicolylamine, and aminomethylphosphonic acid functionalized silicas warrant further exploration

Gaia Early Data Release 3: The celestial reference frame (Gaia-CRF3)

Context. Gaia-CRF3 is the celestial reference frame for positions and proper motions in the third release of data from the Gaia mission, Gaia DR3 (and for the early third release, Gaia EDR3, which contains identical astrometric results). The reference frame is defined by the positions and proper motions at epoch 2016.0 for a specific set of extragalactic sources in the (E)DR3 catalogue. Aims. We describe the construction of Gaia-CRF3 and its properties in terms of the distributions in magnitude, colour, and astrometric quality. Methods. Compact extragalactic sources in Gaia DR3 were identified by positional cross-matching with 17 external catalogues of quasi-stellar objects (QSO) and active galactic nuclei (AGN), followed by astrometric filtering designed to remove stellar contaminants. Selecting a clean sample was favoured over including a higher number of extragalactic sources. For the final sample, the random and systematic errors in the proper motions are analysed, as well as the radio-optical offsets in position for sources in the third realisation of the International Celestial Reference Frame (ICRF3). Results. Gaia-CRF3 comprises about 1.6 million QSO-like sources, of which 1.2 million have five-parameter astrometric solutions in Gaia DR3 and 0.4 million have six-parameter solutions. The sources span the magnitude range G = 13-21 with a peak density at 20.6 mag, at which the typical positional uncertainty is about 1 mas. The proper motions show systematic errors on the level of 12 μas yr-1 on angular scales greater than 15 deg. For the 3142 optical counterparts of ICRF3 sources in the S/X frequency bands, the median offset from the radio positions is about 0.5 mas, but it exceeds 4 mas in either coordinate for 127 sources. We outline the future of Gaia-CRF in the next Gaia data releases. Appendices give further details on the external catalogues used, how to extract information about the Gaia-CRF3 sources, potential (Galactic) confusion sources, and the estimation of the spin and orientation of an astrometric solution

Ethylenediamine-funtionalized ion exchange resin for uranium recovery from acidic mixed sulphate-chloride media: initial column loading studies

A renewed interest in nuclear power around the world to reduce greenhouse gas emission is going to increase demand for uranium as fuel. This increased demand will result in more uranium being mined, which will in turn increase associated environmental pressures, such as fresh water use. A move to lower quality waters containing impurities such as chloride would help alleviate these pressures. In this work uptake characteristics of weakly basic anion exchange resin Ps-EDA towards uranium from saline solutions in a dynamic flow column have been determined. Breakthrough curves were produced, with suppression of uptake being observed for chloride concentrations above 5 g L-1. Calculated resin saturation capacities at 0 and 5 g L-1 chloride are comparable with literature values for strong base anion exchange resins, and exceed those published for weak base resins up to 20 g L-1 chloride. Data has been fit to multiple breakthrough models, with the Modified Dose-Response model most effectively predicting uranium recovery. The results presented show that the ethylenediamine functionality could be suitable for use in future uranium processing flowsheets where a high saline lixiviant is used

p53 expression in dyskeratosis congenita: a marker for oral premalignancy?

As p53 expression has been associated with malignant disease its presence was assessed in biopsy specimens from dorsal lingual hyperkeratosis, taken over a five year period. p53 expression, using CM1, was assessed using a standard immunoperoxidase technique. p53 was not identified in the first biopsy specimen in 1986 but was identified in all subsequent ones. Only in the latest biopsy specimen was there evidence for dysplasia in haematoxylin and eosin stained sections. It is suggested that p53 expression may be a reliable marker for predicting premalignant change in keratoses occurring in dyskeratosis congenita

‘Til Poison Phosphorous Brought them Death’: A potentially occupationally-related disease in a post-medieval skeleton from north-east England

This paper describes the pathological changes observed on the skeleton of a c.12–14 year old person buried in a north-east England Quaker cemetery dated to AD 1711–1857. Bone formation (woven and lamellar) and destruction are present mainly on the mandible, clavicles, sternum and scapulae, long bones of the right arm, left ribs, spine, ilia, and the femora and tibiae. Differential diagnoses of tuberculosis and other pulmonary diseases, smallpox, actinomycosis, neoplastic disease, and “phossy jaw” are considered. While the pathological changes could represent all previously described diseases and thus be associated with the insalubrious conditions in which this person lived, it is also possible that this person worked in the matchmaking industry known to be present in the region at the time. Attention is drawn to the previously overlooked condition “phossy jaw” caused by phosphorus poisoning, which was strongly associated with this industry. While matchstick making was an industry often associated with women and girls, DNA analysis of a bone sample from the skeleton did not successfully identify biological sex. Two dental calculus samples from this person were analysed for phosphorus, and comparisons were made with samples from the same and a different site; the levels did not indicate the person was more exposed to phosphorus than any of the other people at Coach Lane. However, the pathological lesions described also have relevance in a clinical context, because “phossy jaw” has been observed in living populations, arising as a consequence of ingesting phosphorous contained within some pharmaceuticals used for treating neoplastic disease and osteoporosis

Validation of an Instrument to Measure Quality of Life in British Children With Inflammatory Bowel Disease

Objective: To validate IMPACT-III (UK), a health-related quality of life (HRQoL) instrument, in British children with inflammatory bowel disease (IBD). Patients and Methods: One hundred six children and parents were invited to participate. IMPACT-III (UK) was validated by inspection by health professionals and children to assess face and content validity, factor analysis to determine optimum domain structure, use of Cronbach alpha coefficients to test internal reliability, ANOVA to assess discriminant validity, correlation with the Child Health Questionnaire to assess concurrent validity, and use of intraclass correlation coefficients to assess test-retest reliability. The independent samples t test was used to measure differences between sexes and age groups, and between paper and computerised versions of IMPACT-III (UK). Results: IMPACT-III (UK) had good face and content validity. The most robust factor solution was a 5-domain structure: body image, embarrassment, energy, IBD symptoms, and worries/concerns about IBD, all of which demonstrated good internal reliability (α = 0.74–0.88). Discriminant validity was demonstrated by significant (*P < 0.05, **P < 0.01) differences in HRQoL scores between the severe, moderate, and inactive/mild symptom severity groups for the embarrassment scale (63.7* vs 81.0 vs 81.2), IBD symptom scale (45.0** vs 64.2* vs 80.6), and the energy scale (46.4* vs 62.1* vs 77.7). Concurrent validity of IMPACT-III (UK) with comparable domains of the Child Health Questionnaire was confirmed. Test-retest reliability was confirmed with good intraclass correlation coefficients of 0.66 to 0.84. Paper and computer versions of IMPACT-III (UK) collected comparable scores, and there were no differences between the sexes and age groups. Conclusions: IMPACT-III (UK) appears to be a useful tool to measure HRQoL in British children with IBD