Facile Synthesis of the Magnetic Metal Organic Framework Fe3O4@UiO-66-NH2 for Separation of Strontium / 生物医学与环境科学（英文）

A magnetic metal organic framework (MMOF) was synthesized and used to separate Sr2+ in aqueous solution. The shape and structure of prepared Fe3O4@UiO-66-NH2 were characterized, and the absorbed concentration of strontium was determined through inductively coupled plasma mass spectrometry. The results indicated that Fe3O4 and UiO-66-NH2 combined through chemical bonding. The experimental adsorption results for separation of Sr2+ in aqueous solution indicated that the adsorption of Sr2+ to Fe3O4@UiO-66-NH2 increased drastically from pH 11 to pH 13. The adsorption isotherm model indicated that the adsorption of Sr2+ conformed to the Freundlich isotherm model (R2 = 0.9919). The MMOF thus inherited the superior qualities of magnetic composites and metal organic frameworks, and can easily be separated under an external magnetic field. This MMOF thus has potential applications as a magnetic adsorbent for low level radionuclide 90Sr.

Is It Safe to Eat Fish?

No abstract available.

Radioactivity in some sachet drinking water samples produced in Nigeria

Activity concentrations of [40]K, [226]Ra and [228]Ra were measured in some sachet drinking water samples produced in Nigeria. The measurement was done by using high-purity germanium [HPGe] detector [Canberra Industries Inc.]. The measured activity concentrations for [226]Ra [U-series] and [228]Ra [Thseries] were used with their ingested dose conversion factors to estimate annual effective doses for the International Commission on Radiological Protection [ICRP] age groups 0-1y, 1-2y, 2-7y, 7-12y, 12-17y and >17y from consumption of the water samples. Measured activity concentration values varied from 0.57 +/- 0.21 to 34.08 +/- 5.61 Bq l[-1], 2.22 +/- 0.97 to 15.50 +/- 4.51 Bq l[-1] and 0.04 +/- 0.01 to 7.04 +/- 1.16 Bq l[-1] for the radionuclides respectively. Estimated total annual effective doses varied from 4.73 to 49.13, 1.21 to 12.26, 0.86 to 8.54, 1.22 to 11.66, 3.40 to 28.98 and 0.68 to 5.04 mSv y[-1] for the age groups respectively. The highest total annual effective dose was found in Tisco sample while the lowest was found in Focar sample. The total annual effective dose in all samples considerably exceeded the average worldwide ingestion exposure dose value of 0.12 mSv y[-1] from uranium and thorium series reported by the United Nations Scientific Committee on Effects of Atomic Radiations [UNSCEAR]. Therefore the Nigeria populace is advised to consume less of these water samples

Seasonal variations of marine algal community in the vicinity of Uljin nuclear power plant, Korea.

Three marine algal sites were examined seasonally in an area of thermal discharge from the Uljin nuclear power plant in Korea to assess possible impacts from thermal stress. Quadrat samples were taken at three sites: cooling water intake, outfall and Chukbyon. The degree of wave exposure increased from intake, outfallto Chukbyon. Percent cover and biomass were response variables. All sites were, by numbers red algae, followed by brown and green algae. Over the year the maximum species diversity was also found at the Chukbyon (2.39), but the minimal one (1.67) was observed at the outfall. Seasonally generally among algal form-functional groups, filamentous and coarsely branched algae were most abundant throughout the year at the three sites. The numberof species in the jointed calcareous groups increased remarkably at the outfall. Based on these results, species richness appears tobe strongly affected by wave exposure and thermal stress. The higher proportion of calcareous form groups at the outfall sites indicates that these species are better adapted morphologically to thermal stress such as high temperatures.

Uranium, radium and radon exhalation studies in geological samples belonging to some areas of punjab, using track etching technique.

With a view to prospect the uranium, radium and radon concentration and related health risk assessments in areas of Muktsar and Ferozepur districts in Punjab, the fission track registration technique has been used for the analysis of water and soil samples. Uranium content in water ranged from 5.47 to 10.19 microg/l(-1) and 6.28 to 11.74 microg/l(-1) for Muktsar and Ferozepur respectively. Uranium content in soil samples of Muktsar and Ferozepur ranged from 1.14 to 1.90 mg/kg(-1) and 1.26 to 2.44 mg/kg(-1) respectively. Radium concentration in these soil samples has been found to vary from 3.97 to 15.94 bq/kg(-1) and 7.24 to 24.14 bq/kg(-1) for Muktsar and Ferozepur respectively. The radon exhalation values were calculated in terms of area (E(A)) and mass (E(M)). The values of E(M) ranged from 4.9 to 20.6 (mbqkg(-1) hr(-1)) for Muktsar and 9.4 to 31.3 (mbqkg(-1)hr(-1)) for Ferozepur and values of E(A) ranged from 173 to 728 (mbqm(-2)hr(-1)) for Muktsar and 330 to 1102 (mbqm(-2)hr(-1)) for Ferozepur district. These values in general are low and not significant from health hazard point of view. The values of uranium concentration in water samples of these areas are lower than those reported for soil and water samples of Himachal Pradesh. These values are also lower than those reported by Singh et al. for the rocks belonging to uranium and copper mines of Bihar.

Separation and recovery of radioactive and non-radioactive toxic trace elements from aqueous industrial effluents.

An update is presented on liquid membrane-based processes as viable and relevant alternatives to conventional approaches such as precipitation, solvent extraction, ion exchange processes and electrochemical techniques for the removal and recovery of some toxic and/or valuable trace metal ions including some actinides and fission products e.g. U, Am, Y etc and As, Cd, Co, Cr, Cu, Hg, Ni, Pb, Zn etc from radioactive as well as non-radioactive aqueous waste solutions respectively. In particular, results of experiments aimed at developing supported liquid membrane(SLM)-based process using commercially available porous membranes and indigenously prepared track--etch membranes (TEMs) have been critically examined in laboratory studies to generate basic data needed to evaluate their utility for continuous operation without regeneration. These include effect of pore size, porosity, optimum pore size and their reusability. It is clearly demonstrated that indigenously prepared 10 microm thick TEMs with a porosity in the range of 2-5% give comparable transport rates for metal ions-matching with that of commercial membranes of much higher thickness (160 microm) and higher porosity of 60-85%. The smaller thickness of TEMs more than compensates for their lower porosity. It is shown that because of their well defined pore characteristics TEMs could serve as model supports in SLM studies. By comparing the values of permeability coefficient (P) for TEM and polytetraflouroethylene (PTFE) supports for the transport of Pb2+ chosen as a typical divalent metal ion, and using di-2 ethyl hexyl phosphoric acid (D2EHPA) as the carrier, it is unambiguously proved that diffusion of the metal complex across the membrane is the rate controlling step in metal ion transport in SLM-based processes. An overview of the experimental findings along with future outlook and suggestions for further work are presented in this paper.

Radioactive characterization of the Pinheiros river bottom sediment

Radionuclide contents were determined in the botton sediment of the Pinheiros river, into which the Instituto de Pesquisas Energéticas e Nucleares (IPEN) has been continuously discharging low level radioactive liquid effluents. The results showed that the activity of natural radionuclides and the activity of (137)Cs found in the sediment were within the range of the expected baskground for the region. (60)Co was the only other artificial radionuclide detected, with concentrations ranging from 0.20 to 0.85 Ba per kilogram dry weight, at some points of the river.

Vanadium occurrence in Alexandria coastal waters

The present study focused on the occurrence and spatial distribution of vanadium in Alexandria coastal water. Average V concentrations in the investigated water during the period of study were 8.8 mug l-1, 15.6 mug l-1 and 24.4 mug l-1, respectively, for the dissolved particulate and total phases. The spatial distribution of V in the investigated water indicated that the metal enters Alexandria coastal environment mainly from the wastes of the industries located at Abou- Qir and El-Dekhalla area. The relative proportion of the particulate phase in the total V concentration was higher than that of the dissolved phase, respectively, 64% and 36%. The large variations in the total V levels that occurred over the area investigated were due to the variations in the particulate phase concentrations. Alexandria coastal water samples exceeded the V typical concentration for sea water and showed higher V levels in comparison to water of Sargasso Sea, north-west Atlantic Ocean, Gulf of Mexico, Gulf of St. Lawrence and the North Pacific Ocean. The measured V concentrations in the investigated water are comparable to those found in other Mediterranean coastal areas

Avaliaçäo radiossanitária do sistema aquático sob influência do IPEN-CNEN/SP / Radio-sanitary evaluation of aquatic system under influence of Instituto de Pesquisas Energéticas e Nucleares-Comissäo Nacional de Energia Nuclear/Säo Paulo

Com o objetivo de controlar a descarga de material radioativo para o sistema aquático (córrego do Jaguaré e rio Pinheiros) sob influência do IPEN-CNEM/SP é feita a monitoraçäo dos efluentes líquidos gerados por suas diversas instalaçöes nucleares, antes de sua liberaçäo para o meio ambiente. Este controle é feito medindo-se primeiramente, por espectrometria gama e/ou espectrofotometria, a atividade de cada um dos radionuclídeos contidos nos efluentes ("termo-fonte"), a seguir os resultados säo comparados com os limites de descarga adotados pela Comissäo Nacional de Energia Nuclear, quando entäo é autorizada a sua liberaçäo. No ano de 1988 foi liberada uma atividade total de 1997, 9 x 106 Bq em um volume total de 2421,4 m3. A partir do conhecimento do "termo-fonte" e de dados referentes à análise do local, foi feita a estimativa da dose equivalente efetiva recebida pelos indivíduos do público que permanecem próximos aos pontos de descarga dos efluentes no rio Pinheiros, levando-se em conta que a única via possível de exposiçäo é a irradiaçäo externa gama destes indivíduos. O resultado encontrado foi de 39,4nSv, sendo que os radionuclídeos que mais contribuíram para essa dose foram 60Co, 137Cs, 131I e 226Ra. Esse valor esté abaixo de 1/10 do limte de dose máximo admissível estabelecido pelas Normas de Proteçäo Radiológica que é de 10-3Sv/ano. De forma a se medir "in loco" os níveis de radioatividade recebidos pelos indivíduos do público foram coletadas e analisadas, por espectrometria gama e fluorimetria, amostras de água subterranea, água de superfície e sedimento do rio Pinheiros. Nestas amostras foram detectados apenas 226Ra, 228Ra, UNat, 40K e 7Be em concentraçöes correspondentes aos níveis de radioatividade natural. A partir destes resultados e do cálculo da dose equivalente pode-se concluir que o impacto causado no meio aquático sob influência do IPEN-CNEN/SP é despresível