Relationships Between Bone Treatment Conditions and Co2+ Sorption Capacities

Co-60 is an important radionuclide in spent nuclear fuel and liquid radioactive wastes. For the purification of water containing Co2+, ions sorption on hydroxyapatite (Ca-10(PO4)(6)(OH)(2)) can be applied. The process is particularly cost-effective if biological apatite from animal bones is utilized. In this study, dependence between bovine bone treatment conditions and Co2+, sorption was investigated as a function of initial metal concentration. Eight sorbents were previously prepared using fractional factorial design, by simultaneous variations of five process variables between two levels: factor A-the type of the chemical reagent (H2O2 or NaOH), factor B-reagent concentration (0.1 mol/L or 2 mol/L), factor C-reaction temperature (20(o)C or 60(o)C), factor D-contact time (1h or 3h) and factor E-sample annealing (without or at 400(o)C). At this point, the effects of treatment factors on Co2+, sorption efficiency were evaluated using statistical analysis. Amounts of Co2+ sorbed, amounts of released Ca2+ ions and final pH values were considered as system responses. The results showed that the impact of various treatment factors was different for different starting concentrations of Co2+. Consequently, no statistically important relations could be established between treatment conditions and Co2+, sorption from 10(-4) and 5*10(-4) mol/L solutions, whereas thermal treatment at 400(o)C was the only statistically significant factor influencing sorption from the most concentrated solution (5*10(-3) mol/L). Depending on initial Co2+, concentration, various factors had statistically significant effect on equilibrium pH values, whereas no relation was found between bone treatment conditions and the amounts of Ca2+, released during the sorption.3rd International Conference on Radiation and Applications in Various Fields of Research (RAD), Jun 08-12, 2015, Budva, Montenegr

Leaching kinetics of Co(II) and Sr(II) contaminated soil via chemical extraction method

Artificially contaminated soil, with mixture of Co(II) and Sr(II) ions in different proportions, was tested. The main aim was to investigate the possibility of ethylenediamine-tetraacetic acid (EDTA) utilization in the chemical extraction process as a method for soil remediation in the case of mixed contamination. The efficiency of this process when EDTA of 10 -4 molL -1 was used was low, while the application of the EDTA solution of the initial concentration 5 · 10 -3 molL -1 or higher showed almost the same efficiency. This suggested that the application of the solution EDTA (5 · 10 -3 molL -1 ) is optimal from the aspect of cost and degradation of soil properties. Furthermore, process kinetic was fitted using one parameter shrinking core models. Kinetic data modeling showed that the process is complex, demanding multi resistance kinetic model. © 2018, Vinca Inst Nuclear Sci. All rights reserved

New materials for separation of radioactive strontium from the sea water

Otpuštanje 90Sr umora i okeane kao posledica testiranja nuklearnog naouružanja i akcidenata u nuklearnim objektima podstaklo je razvoj novih, jednostavnijih i bržih metoda i materijala za njegovu separaciju. Monitoring morske vode u slučaju akcidentnesituacije, kao i dekontaminacija tečnog otpada koji sadrži morsku vodu, predstavljaju izuzetno zahtevne zadatke usled složenog hemijskog sastava i visokog saliniteta matriksa. U ovom radu dat je pregled najnovijih rezultata u oblasti razvoja materijala sapotencijalom selektivnog vezivanja Sr-jona iz morske vode. Diskutovani su mehanizmi vezivanja i performanse različitih materijala sa aspekta primene u praksi i perspektivnih pravaca budućih istraživanja.The release of 90Sr into the sea and oceans as a result of testing nuclear weapons and accidents in nuclear facilities has prompted the development of new, simpler and faster methods and materials for its separation. The monitoring of seawater in the event of an accident, as well as decontamination of liquid waste containing sea water, represent extremely demanding tasks due to the complex chemical composition and high salinity of the matrix. This paper presents an overview of the latest results in the field of material development with the potential for selective binding of Sr-ions from seawater. Mechanisms of binding and performance of different materials are discussed from the aspect of an application in practice and directions of future research.Proceedings: [http://vinar.vin.bg.ac.rs/handle/123456789/8681]XXX симпозијум ДЗЗСЦГ (Друштва за заштиту од зрачења Србије и Црне Горе), 2- 4. октобар 2019. године, Дивчибаре, Србиј

Mobility of Co2+ and Sr2+ ions in the contaminated soil: column study

The mobility of pollutants in the soil is closely related to their toxicity, and thus very important information for the selection of remediation strategies. In this study, leaching of Sr2+ and Co2+ ions from contaminated soil was investigated and compared under dynamic conditions. As a model soil, a sample from the “Vinča” Institute was tested. The soil artificially contaminated with inactive Sr2+ and Co2+ ions was packed in the columns, while acidic rain water was used as a leaching solution. Desorption of both cations was the most pronounced at the beginning, reaching the peak after the second day for Co2+ and after the seventh day for Sr2+. During the course of experiment (37 days), cumulative percentages of desorbed Co2+ and Sr2+ were 0.7% and 19.8 %, respectively. The results indicated significantly higher soil affinity towards Co2+ ions. In spite of its higher total concentration in the soil, Co2+ mobility was much lower compared to Sr2+

Stability of Co 2+, Sr 2+ and Ni 2+ ions sorbed onto waste ceramic and roof tiles

Građevinski otpad, kao inertan čvrsti otpad, zauzima značajne kapacitete komunalnih deponija. U ovom radu ispitana je mogućnost valorizacije otpadnih keramičkih pločica i crepa, kao silikatnih matrica za uklanjanje jona Co2+, Sr2+ i Ni2+ iz trokomponentne smeše. U cilju utvrđivanja stabilnosti veza uspostavljenih između katjona i sorbenata, primenjena je metoda sekvencijalne ekstrakcije. Sorpcija jona Sr2+ je bila najmanje efikasna, usled kompeticije između jona u polaznoj smeši i značajne količine konkurentnih Ca2+ jona otpuštenih iz otpadnih materijala. Sorbovani joni Sr2+ su u visokom procentu ekstrahovani u okviru jonoizmenjivačke frakcije i frakcije rastvorne u slabim kiselinama, te su pokazali i najmanju stabilnost. Nasuprot tome, ispitani materijali su sorbavali Co2+ i Ni2+ jone u značajnoj količini, a njihova distribucija ukazuje na uspostavljanje jačih hemiskih veza. Uzimajući u obzir, količine, dostupnost i hemijsku kompatibilnost sa solidifikacionim matriksima koji se koriste za trajno odlaganje radioaktivnog otpada, rezultati ukazuju na potencijal primene građevinskog otpada umesto prirodnih mineralnih sorbenata.Construction and demolition waste is an inert solid waste which occupies significant capacities of the municipal landfills. The possibility of the valorization of waste ceramic and roof tiles, as silicate matrices for Co2+, Sr2+ and Ni2+ removal from three-component solution, was explored. In order to determine the stability of the bonds established between the cations and the sorbents, the method of sequential extraction was applied. Sr2+ sorption was the least efficient, due to the competition with other cations in the starting mixture and significant amounts of concurrent Ca2+ ions released from the waste materials. High percentages of sorbed Sr2+ ions were extracted in ion-exchangeable and acid soluble fractions, showing the lowest stability. On the other hand, Co2+ and Ni2+ sorption was more efficient and their distribution implies establishment of stronger chemical bonds. Taking into account the amounts, availability and chemical compatibility with matrixes for radioactive waste solidification and disposal, the obtained results demonstrate the potential applicability of construction and demolition waste as an alternative to natural mineral sorbents.Зборник радова : XXIX симпозијум ДЗЗСЦГ : Сребрно језеро, 27-29. септембар 2017. годин

Stability of Co 2+, Sr 2+ and Ni 2+ ions sorbed onto waste ceramic and roof tiles

Građevinski otpad, kao inertan čvrsti otpad, zauzima značajne kapacitete komunalnih deponija. U ovom radu ispitana je mogućnost valorizacije otpadnih keramičkih pločica i crepa, kao silikatnih matrica za uklanjanje jona Co2+, Sr2+ i Ni2+ iz trokomponentne smeše. U cilju utvrđivanja stabilnosti veza uspostavljenih između katjona i sorbenata, primenjena je metoda sekvencijalne ekstrakcije. Sorpcija jona Sr2+ je bila najmanje efikasna, usled kompeticije između jona u polaznoj smeši i značajne količine konkurentnih Ca2+ jona otpuštenih iz otpadnih materijala. Sorbovani joni Sr2+ su u visokom procentu ekstrahovani u okviru jonoizmenjivačke frakcije i frakcije rastvorne u slabim kiselinama, te su pokazali i najmanju stabilnost. Nasuprot tome, ispitani materijali su sorbavali Co2+ i Ni2+ jone u značajnoj količini, a njihova distribucija ukazuje na uspostavljanje jačih hemiskih veza. Uzimajući u obzir, količine, dostupnost i hemijsku kompatibilnost sa solidifikacionim matriksima koji se koriste za trajno odlaganje radioaktivnog otpada, rezultati ukazuju na potencijal primene građevinskog otpada umesto prirodnih mineralnih sorbenata.Construction and demolition waste is an inert solid waste which occupies significant capacities of the municipal landfills. The possibility of the valorization of waste ceramic and roof tiles, as silicate matrices for Co2+, Sr2+ and Ni2+ removal from three-component solution, was explored. In order to determine the stability of the bonds established between the cations and the sorbents, the method of sequential extraction was applied. Sr2+ sorption was the least efficient, due to the competition with other cations in the starting mixture and significant amounts of concurrent Ca2+ ions released from the waste materials. High percentages of sorbed Sr2+ ions were extracted in ion-exchangeable and acid soluble fractions, showing the lowest stability. On the other hand, Co2+ and Ni2+ sorption was more efficient and their distribution implies establishment of stronger chemical bonds. Taking into account the amounts, availability and chemical compatibility with matrixes for radioactive waste solidification and disposal, the obtained results demonstrate the potential applicability of construction and demolition waste as an alternative to natural mineral sorbents.Зборник радова : XXIX симпозијум ДЗЗСЦГ : Сребрно језеро, 27-29. септембар 2017. годин

Analysis of factors influencing Cu(II) sorption by clinoptiolite

The effects of initial metal concentration and pH, as well as the sorbent mass and particle size, on Cu(II) sorption by natural clinoptilolite were evaluated and compared. Full factorial experimental design at two levels was applied. Statistically significant factors were determined considering residual Cu(II) concentrations as a system response.Physical chemistry 2012 : 11th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 24-28 September 201

Optimization of Sr-ion extraction from the contaminated soil using Box-Benken design

Among the factors that affect the degradation of soil quality, contamination with radioactive substances has gained significance due to the fast development and exploitation of nuclear energy. The remediation measures based on physical, chemical and biological principles aim to reduce the adverse effects of ionizing radiation on the ecosystem as a whole, either by radionuclide separation from the soil matrix or by their solidification/stabilization. The selection of suitable method is carried out for each individual case of contamination, as it depends on the soil type, the pollutant type, distribution, and the level of contamination, area that needs to be treated, overall cost, etc. In order to develop a site-specific treatment, optimization of the method performance is required through the extensive research on the effects of a large number of variables. In such cases, experimental design methodology (DOE) represents a useful approach for the comparison of different treatments and their optimization. In contrast to the conventional strategy of varying one factor at the time, DOE implies a simultaneous variation of all factors in order to disclose the most influential factors, the significant interactions between the factors, and the optimal levels of the factors. In the present study, the problem of soil contamination with 90Sr was addressed. Previous investigations on Sr-ions distribution in the soil have revealed their preferential association with the ion-exchangeable sites, regardless of the soil type, contamination level and aging time. High mobility of Sr in the soil is, therefore, the property that makes the separation by chemical extraction a simple and economical option since the effects can be achieved using solutions of competing cations. The soil, sampled at the site of the Vinča Institute of Nuclear Science and the Public Company Nuclear Facilities of Serbia, was artificially contaminated with Sr-ions. The Box-Benken design was used for the analysis of soil remediation efficiency using Ca(NO3)2 as an extracting agent. Reagent concentration, soil/liquid ratio and contact time were considered as process variables, whereas the amounts of extracted cations and the final pH values were monitored as the response functions. The applicability of different mathematical models, with the inclusion of linear or quadratic terms, was tested for the description of experimental results. Analysis of variance of the chosen responses showed that Sr extraction efficiency was primarily affected by the variation of the reagent concentration. By proper selection of the levels of investigated factors, complete removal of Sr was achieved. Furthermore, DOE enabled the prediction of system responses, which makes it a significant tool in practical applications.VII International Conference on Radiation in Various Fields of Research : RAD 2019 : book of abstracts; June 10-14, 2019; Herceg Novi, Montenegr

Синтетички пут за синтезу потенцијалних, бивалентних лиганада који поседују опоидну и допамин Д2/Д3 фармакогфору

A scalable, cost-efficient and simple synthetic pathway towards potential bivalent opioid/dopamine receptor ligands was developed and optimized. Three novel compounds that contain both opioid and dopamine pharmacophores linked by the four methylene group chain were synthesized in 33, 35 and 39 % overall yield after a four-step synthetic route starting from three commercially available N-aryl piperazines. The anilino piperidine precursor was easily prepared in three steps, as previously published, starting from 4- piperidone. The synthesis presented in this paper could be of interest for heterocyclic and general organic chemistry. The newly designed compounds possessing two pharmacophores, opioid and D2/D3, are potentially useful pharmacological probes. Of particular interest would be the simultaneous binding to both opioid and D2/D3 receptors, and the resulting pharmacological responses may be useful for the further understanding of tolerance and dependence phenomena in opioid clinical use and/or abuse.Три нова једињења, која садрже опиоидну и допаминску фармакофору, спојене преко четири метиленске групе, синтетисанa су у четири фазе у укупном приносу од приближно 35 %, полазећи од три комерцијално доступна N-арилпиперазина. Анилино- пиперидински прекурсор је добијен у три једноставне реакционе фазе, полазећи од 4-пиперидона, према познатој литературној методи. Синтеза приказана у овом раду може бити од значаја за хетероцикличну и органску хемију у целини. Новосинтетисана једињења која поседују две фармакофоре, опиоидну и Д2/Д3, су потенцијално корисни супстрати за фармаколошка испитивања. Од посебног интереса може бити истовремено везивање за опиоидне и Д2/Д3 рецепторе, а резултујући фармаколошки одговор био би користан у даљем разумевању толеранције и зависности, као феномена везаних за кли- ничку употребу и/или злоупотребу опијата

Radioactive waste and decontamination: Retrospective of papers presented on Symposiums of the Radiation protection society in the period 1963-2017

Kao neizbežni pratioci svih vidova proizvodnje i primene nuklearne energije nastaju nusprodukti -otpadni materijali, koji nemaju potencijala za dalje korišćenje, a čija aktivnost premašuje granične vrednosti propisane zakonskom regulativom. Akcidenti pri proizvodnji i primeni nuklearne energije, manipulaciji i transportovanju izvora jonizujućeg zračenja i druge vanredne situacije u miru i ratu, značajno doprinose generisanju radioaktivnog otpada kao i radijacionoj kontaminaciji materijalnih sredstava i objekata, životne sredine i živih bića. Povodom jubilarnog XXX Simpozijuma Društva za zaštitu od zračenja Srbije i Crne Gore, kroz restrospektivu radova saopštenih na prethodnim skupovima prikazano je kako su se na vremenskoj skali od 54 godine menjale aktualne teme, problemi, metodologija rada i koji su zaključci proistekli iz naučnih istraživanja i praktičnog rada u oblasti radiokativnog otpada i dekontaminacije.As inevitable followers of all forms of production and application of nuclear energy, waste materials are produced which do not have the potential for further use and which activity exceeds the limit values prescribed by the legislation. Accidents in the production and application of nuclear energy, manipulation, and transportation of sources of ionizing radiation, and other emergencies in peace and war, contribute significantly to the generation of radioactive waste as well as to the radiation contamination of material assets and objects, the environment and living beings. On the occasion of the jubilee XXX Symposium of the Society for Radiation Protection of Serbia and Montenegro, through the retrospection of the papers presented at the previous meetings, the current topics have been tracked on the timeline of 54 years, as well as the problems, the methodology of work and significant conclusions derived from scientific research and in practice.Proceedings: [http://vinar.vin.bg.ac.rs/handle/123456789/8681]XXX симпозијум ДЗЗСЦГ (Друштва за заштиту од зрачења Србије и Црне Горе), 2- 4. октобар 2019. године, Дивчибаре, Србиј