The document summarizes recent advances in studies of technetium in environmentally focused contexts. It discusses technetium sources such as nuclear power plants and reprocessing facilities, and how technetium is handled in radioactive waste through various approaches like dilution, underground injection, storage, and vitrification. It also examines technetium behavior during underground storage of high-level radioactive waste and speciation in simulated radioactive waste conditions.
2018 History of technetium studies in Russia Anna KuzinaKonstantin German
Lecture is about the History of technetium studies in Russia and Anna Kuzina 100 anniversary of birthday
Technetium separation in milligram, gram and kilogram ammounts 1957 - 1993
The peer-reviewed International Journal of Engineering Inventions (IJEI) is started with a mission to encourage contribution to research in Science and Technology. Encourage and motivate researchers in challenging areas of Sciences and Technology.
2018 History of technetium studies in Russia Anna KuzinaKonstantin German
Lecture is about the History of technetium studies in Russia and Anna Kuzina 100 anniversary of birthday
Technetium separation in milligram, gram and kilogram ammounts 1957 - 1993
The peer-reviewed International Journal of Engineering Inventions (IJEI) is started with a mission to encourage contribution to research in Science and Technology. Encourage and motivate researchers in challenging areas of Sciences and Technology.
Maiyalagan,Electrochemical oxidation of methanol on pt v2 o5–c composite cata...kutty79
Platinum nanoparticles have been supported on V2O5–C composite through the reduction of chloroplatinic
acid with formaldehyde. The catalyst was characterized by X-ray diffraction and transmission electron
microscopy. Catalytic activity and stability for the oxidation of methanol were studied by using
cyclic voltammetry and chronoamperometry. Pt/V2O5–C composite anode catalyst on glassy carbon electrode
show higher electro-catalytic activity for the oxidation of methanol. High electro-catalytic activities
and good stabilities could be attributed to the synergistic effect between Pt and V2O5, avoiding the electrodes
being poisoned.
Review on recent progress in nitrogen doped graphene synthesis, characterizat...materials87
Nitrogen doping has been an effective way to
tailor the properties of graphene and render its potential use
for various applications. Three common bonding configurations
are normally obtained when doping nitrogen into the
graphene: pyridinic N, pyrrolic N, and graphitic N. This paper
reviews nitrogen-doped graphene, including various synthesis
methods to introduce N doping and various characterization
techniques for the examination of various N bonding
configurations. Potential applications of N-graphene are also
reviewed on the basis of experimental and theoretical studies
Visible light assisted photocatalytic reduction of CO2 using a graphene oxide...Pawan Kumar
A new heteroleptic ruthenium complex containing 2-thiophenyl benzimidazole ligands was synthesized using a microwave technique and was immobilized to graphene oxide via covalent attachment. The synthesized catalyst was used for the photoreduction of carbon dioxide under visible light irradiation without using a sacrificial agent, which gave 2050 μmol g−1 cat methanol after 24 h of irradiation
Detection of the Presence of Heavy Metal Pollutants in Eleme Industrial Area ...theijes
The presenceof some heavy metal pollutants which are deposited on soil in the Eleme environment due to the operational activities of some companies in the area have been studied. Some soil samples in areas situated around industrial installations were collected and analyzed using Atomic Absorption Spectrophotometer (AAS). Results obtained show the presence and concentration distributions of nine heavy metals. The metals are Iron (Fe), Manganese (Mn), Zinc (Zn), Lead (Pb), Copper (Cu), Chromium (Cr), Cobalt (Co) and Cadmium (Cd). It was observed that over 90% of each of the metals was located in communities hosting the industrial corporations while the remaining 10% is distributed to areas away from the source or host communities. This reveals that, a link exists between the pollutants and the activities of these industries.
Maiyalagan,Electrochemical oxidation of methanol on pt v2 o5–c composite cata...kutty79
Platinum nanoparticles have been supported on V2O5–C composite through the reduction of chloroplatinic
acid with formaldehyde. The catalyst was characterized by X-ray diffraction and transmission electron
microscopy. Catalytic activity and stability for the oxidation of methanol were studied by using
cyclic voltammetry and chronoamperometry. Pt/V2O5–C composite anode catalyst on glassy carbon electrode
show higher electro-catalytic activity for the oxidation of methanol. High electro-catalytic activities
and good stabilities could be attributed to the synergistic effect between Pt and V2O5, avoiding the electrodes
being poisoned.
Review on recent progress in nitrogen doped graphene synthesis, characterizat...materials87
Nitrogen doping has been an effective way to
tailor the properties of graphene and render its potential use
for various applications. Three common bonding configurations
are normally obtained when doping nitrogen into the
graphene: pyridinic N, pyrrolic N, and graphitic N. This paper
reviews nitrogen-doped graphene, including various synthesis
methods to introduce N doping and various characterization
techniques for the examination of various N bonding
configurations. Potential applications of N-graphene are also
reviewed on the basis of experimental and theoretical studies
Visible light assisted photocatalytic reduction of CO2 using a graphene oxide...Pawan Kumar
A new heteroleptic ruthenium complex containing 2-thiophenyl benzimidazole ligands was synthesized using a microwave technique and was immobilized to graphene oxide via covalent attachment. The synthesized catalyst was used for the photoreduction of carbon dioxide under visible light irradiation without using a sacrificial agent, which gave 2050 μmol g−1 cat methanol after 24 h of irradiation
Detection of the Presence of Heavy Metal Pollutants in Eleme Industrial Area ...theijes
The presenceof some heavy metal pollutants which are deposited on soil in the Eleme environment due to the operational activities of some companies in the area have been studied. Some soil samples in areas situated around industrial installations were collected and analyzed using Atomic Absorption Spectrophotometer (AAS). Results obtained show the presence and concentration distributions of nine heavy metals. The metals are Iron (Fe), Manganese (Mn), Zinc (Zn), Lead (Pb), Copper (Cu), Chromium (Cr), Cobalt (Co) and Cadmium (Cd). It was observed that over 90% of each of the metals was located in communities hosting the industrial corporations while the remaining 10% is distributed to areas away from the source or host communities. This reveals that, a link exists between the pollutants and the activities of these industries.
The rare-earth elements (REEs) are becoming increasingly important in the transition to a green economy,
due to their essential role in permanent magnets, lamp phosphors, catalysts, rechargeable batteries
etc. With China presently producing more than 90% of the global REE output and its increasingly tight
export quota, the rest of the world is confronted with a REE supply risk. Mining companies are now
actively seeking new exploitable REE deposits while some old mines are being reopened. Because of the
absence of economical and/or operational primary deposits on their territory, many countries will have
to rely on recycling of REEs from pre-consumer scrap, industrial residues and REE-containing End-of-Life
products. REE recycling is also recommended in view of the so-called “balance problem”. For instance,
primary mining of REE ores for neodymium generates an excess of the more abundant elements, lanthanum
and cerium. Therefore, recycling of neodymium can reduce the total amount of REE ores that
need to be extracted. Despite a vast, mostly lab-scale research effort on REE recycling, up to 2011 less
than 1% of the REEs were actually recycled. This is mainly due to inefficient collection, technological
problems and, especially, a lack of incentives. A drastic improvement in the recycling of REEs is, therefore,
an absolute necessity. This can only be realized by developing efficient, fully integrated recycling routes,
which can take advantage of the rich REE recycling literature. This paper provides an overview of this
literature, with emphasis on three main applications: permanent magnets, nickel metal hydride batteries
and lamp phosphors. The state of the art in preprocessing of End-of-Life materials containing REEs and
the final REE recovery is discussed in detail. Both pyrometallurgical and hydrometallurgical routes for
REE separation from non-REE elements in the recycled fractions are reviewed. The relevance of Life Cycle
Assessment (LCA) for REE recycling is emphasized. The review corroborates that, in addition to mitigating
the supply risk, REE recycling can reduce the environmental challenges associated with REE
mining and processing.
Using Tunisian Phosphate Rock and Her Converted Hydroxyapatite for Lead Remov...IJERA Editor
Natural and synthesis apatites represent a cost effective soil amendment, which can be used for in situ reduction of lead bioavailability and mobility. In our previous work, we selected Tunisian Phosphate Rock (TPR) and Hydroxyapatite (CaHAp) as promising minerals for the removal of lead from aqueous solutions. X-ray powder diffraction patterns (DRX), Infra Red (IR), Thermogravimetric analysis (TGA) and Scanning Electron Microscopy (SEM) were used to characterize TPR and CaHAp. CaHAp was prepared from TPR and employed for the removal of Pb2+ ions at different concentrations from aqueous solution to determine the adsorption properties of CaHAp and compare them with those of a TPR. The kinetic data obtained indicated that the adsorption performances of the adsorbents depended both on their specific surface area and crystallinity. Complexation of lead ion on the adsorbent surface favoured the dissolution of hydroxyapatites characterized by a Ca/Pb molar ratio of 1.69. The maximum adsorption capacity of CaHAp for Pb2+ ions at 25 °C was 1.806 mmol /g relative to 1.035 mmol /g for TPR at the same temperature. The higher capacity of CaHAp was explained in terms of its porosity and crystallinity. The Pb2+ ions sorption results could be modelled by the Langmuir and Freundlich isotherms. The simulations of adsorption isotherms of Pb2+ on CaHAp allow us to conclude that there is a good correlation between the experimental data and the Langmuir model. On TPR, we show a good correlation between the experimental data and the Langmuir and Freundlich model.
Characterization and Dielectric Study of Mihaliccik Tremoliteijtsrd
The natural tremolite Ca2Mg5Si8O22 OH 2 was obtained from Mihaliccik district of Eskisehir, Turkey 39.8787N 31.3806E . It is a part of the amphibole family of silicate minerals. All the phases were described by X ray diffraction XRD , energy dispersive spectroscopy EDXRF , Raman, and Fourier transform infrared spectroscopy FTIR . The natural tremolite specimen used in this study includes mostly 54.4 SiO2, 22.82 MgO, 15.04 CaO, and 1.45 Al2O3. The natural tremolite sample used for the present investigation was not pure. The impurity was calcite. The FTIR spectrum and the Raman spectrum were recorded for natural tremolite sample in the range of 4000 and 350 cm 1 and 4000 and 70 cm 1 at room temperature, respectively. The natural tremolite and fired tremolite samples were prepared for this investigation. Dielectric measurements were realized in the 3 kHz ' 1 MHz frequency region and at the room temperature by using HP4192A LF Impedance Analyzer. The dielectric parameters of the samples were obtained the conclusions of the study were explained and given to be used for further investigations in some industrial productions. Ertugrul Izci "Characterization and Dielectric Study of Mihaliccik Tremolite" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-4 | Issue-1 , December 2019, URL: https://www.ijtsrd.com/papers/ijtsrd29671.pdf Paper URL: https://www.ijtsrd.com/engineering/mineral-and-metallurgical-engineering/29671/characterization-and-dielectric-study-of-mihaliccik-tremolite/ertugrul-izci
MACROMOLECULAR COMPOUNDS AND GELS. A manual for students and graduate students of biotechnology training and medical universities (in Russian) Authors: Belova EV, German KE, Afanasyev AV, Slyusar OI, Solodova EV
Proceedings and selected lectures 10th intern symp technetium rheniumKonstantin German
Proceedings and selected lectures of the 10th International Symposium on Technetium and Rhenium – Science and Utilization, October 3-6, 2018 - Moscow – Russia, Eds: K. German, X. Gaona, M. Ozawa, Ya. Obruchnikova, E. Johnstone, A. Maruk, M. Chotkowski, I. Troshkina, A. Safonov. Moscow: Publishing House Granica, 2018, 518 p.
ISBN 978-5-9933-0132-7 December 2018
Aleksey Buryak. WELCOME ADDRESS FROM IPCE - RUSSIAN ACADEMY OF SCIENCES Andrey Romanov. WELCOME ADDRESS FROM THE MINISTRY OF SCIENCE AND HIGHER EDUCATION OF RUSSIAN FEDERATION Mikhail Igorevich Panasyuk. ANNA KUZINA: BIOGRAPHY. K.E. German. PROF. ANNA FEDOROVNA KUZINA – 100TH ANNIVERSARY OF BIRTHDAY T. Yoshimura, M. Seike, H. Ikeda, K. Nagata, A. Ito, E. Sakuda, N. Kitamura, A. Shinohara PHOTOLUMINESCENCE SWITCHING OF NITRIDORHENIUM(V) COMPLEXES B. Grambow, X. Gaona, W. Runde, R. Konings, A.V. Plyasunov, L. Rao, A.L. Smith, E. Moore, M.-E. Ragoussi, J. Martinez-Gonzalez, I. Grenthe. CHEMICAL THERMODYNAMICS OF TECHNETIUM IN THE OECD/NEA UPDATE VOLUME E.S. Kulikova, Zh.K. Majed, D.V. Drobot, E.I. Efremova. HIGHLY SELECTIVE CATALYSTS BASED ON BIMETALLIC RHENIUM-RUTHENIUM COMPLEXES OBTAINED BY ALKOXYTECHNOLOGY E.S. Kulikova, D.V. Drobot, E.I. Efremova. THE FIRST EXAMPLE OF BI AND THREEMETALLIC ALKOXIDES CONTAINING RHENIUM AND RUTHENIUM T. Matsuzaki, H. Sakurai. A NEW PRODUCTION METHOD OF 99Mo BY MUON NUCLEAR TRANSMUTATION N. Budantseva, G. Andreev, A. Fedoseev THE U(VI), NP(VI) AND PU(VI) COMPLEXES WITH TcO4-, ReO4-. THE DIFFICULTIES IN ASSIGNING OF AnO22+ GROUPS VIBRATIONAL FREQUENCIES. J.S. McCloy, C. Soderquist, J. Weaver, Jason Lonergan. SPECTROSCOPIC STUDIES OF ALKALI PERTECHNETATES
Молекулы белков лежат в основе почти всех биологических процессов. Ученым всегда были любопытны как белки, участвующие в метаболических путях, так и молекулярные основы их функционирования. Однако в эру системной биологии еще больше внимание уделяется полному пониманию работы всей совокупности белков организма, его протеома. Все более важно, что мы не только понимаем все стороны данной функции, или функций, какого-либо белка, но и то, что наше знание распространяется на все компоненты изучаемой системы или организма и так далеко, насколько это возможно. Без всестороннего анализа информации попытки синтеза и расчетов не смогут выйти за рамки приближенной реальности.
Книга "Структура и функционирование белков: Применение методов биоинформатики" представляет собой уникальный обзор современного состояния вопросов моделирования структуры белков и предсказания их функции. Книга написана ведущими специалистами в своей области, прекрасно иллюстрирована и содержит ссылки на доступные серверы и другие ресурсы, которые читатель, возможно, захочет использовать в своей научной работе. В конце каждой главы описываются перспективы развития и наиболее актуальные проблемы соответствующих областей науки.
Физико-химические методы исследования в медицине и биологии: Учебное пособие / Медицинский университет Реавиз. Москва, Издательство «Граница», 2016. 120 с.
Данное учебное пособие написано в соответствии с содержанием Государственных образо-вательных стандартов и программой дисциплины “Физико-химические методы анализа” по специальности “Медицина”, направлению и программой большого практикума (раздел “Физикохимические методы анализа”), который выполняется студентами по специальности “Биология”.
В нем изложены основы физико-химических методов анализа. Рассмотрены условия и области применения методов, их достоинства и недостатки, ограничения, перспективы развития и другие особенности и характеристики.
В конце каждой главы дано описание практических работ, приведены контрольные вопросы.
Предназначено для студентов-медиков, биологов, химиков, аспирантов, научных работников и учителей школ.
2016 rsc-advance-tc-c-qinggao wang - 6 pp 16197-16202Konstantin German
We analyze the formation of transition metal (TM) carbides, as determined by the strength of TM–TM and
TM–C bonds, as well as lattice distortions induced by C interstitials. With increasing filling of the d-band of
TMs, TM–C bonds become increasingly weak from the left of the periodic table to the right, with fewer and
fewer C atoms entering the TMs lattice. Technetium (Tc) turns out to be a critical point for the formation of
carbides, guiding us to resolve a long-standing dispute. The predicted Tc carbides, agreeing with measured
X-ray absorption spectra, should decompose to cubic Tc and graphite above 2000 K. Consequently, we
show that what has been claimed as TcC (with rocksalt structure) is actually a high-temperature cubic
phase of elemental technetium.
своевременная диагностика и терапия данного заболевания до сих пор являются нерешенной клинической задачей. По данным на 2011 г., заболе-
ваемость раком простаты в России составила 10,7% (40 тыс. первичных случаев) мужского населения, причем в 60% случаев заболевание диа-
гностировали на поздней (III–IV) стадии, когда неизбежен процесс активного роста и распространения метастазов. Методы анатомической
визуализации при диагностике данного заболевания имеют низкую чувствительность и специфичность. Методы метаболической визуализации,
использующие в качестве маркера простатспецифический антиген (ПСА), также малоэффективны. В качестве маркера для диагностики и
лечения метастатического рака простаты предлагается рассматривать простатспецифический мембранный антиген (ПСМА). За рубежом
проходят клинические испытания наиболее перспективные диагностические радиофармпрепараты на основе малых пептидных молекул, моди-
фицированных мочевиной, которые отличаются наибольшим сродством к ПСМА. Отличительной особенностью этих соединений является их
благоприятная фармакокинетика, высокое и длительное накопление в опухоли и метастазах, быстрое выведение из организма.
Ключевые слова: метастатический рак предстательной железы, простатспецифический мембранный антиген, радиофармпрепараты.
(Для цитирования: Власова О.П., Герман К.Э., Крылов В.В., Петриев В.М., Эпштейн Н.Б. Новые радиофармпрепараты для диагности-
ки и терапии метастатического рака предстательной железы на основе ингибиторов простатспецифического мембранного антигена.
Вестник РАМН. 2015; 70 (3): 360–365. Doi: 10.15690/vramn.v70i3.1334)
Exploiting Artificial Intelligence for Empowering Researchers and Faculty, In...Dr. Vinod Kumar Kanvaria
Exploiting Artificial Intelligence for Empowering Researchers and Faculty,
International FDP on Fundamentals of Research in Social Sciences
at Integral University, Lucknow, 06.06.2024
By Dr. Vinod Kumar Kanvaria
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
A Strategic Approach: GenAI in EducationPeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
Macroeconomics- Movie Location
This will be used as part of your Personal Professional Portfolio once graded.
Objective:
Prepare a presentation or a paper using research, basic comparative analysis, data organization and application of economic information. You will make an informed assessment of an economic climate outside of the United States to accomplish an entertainment industry objective.
Acetabularia Information For Class 9 .docxvaibhavrinwa19
Acetabularia acetabulum is a single-celled green alga that in its vegetative state is morphologically differentiated into a basal rhizoid and an axially elongated stalk, which bears whorls of branching hairs. The single diploid nucleus resides in the rhizoid.
June 3, 2024 Anti-Semitism Letter Sent to MIT President Kornbluth and MIT Cor...Levi Shapiro
Letter from the Congress of the United States regarding Anti-Semitism sent June 3rd to MIT President Sally Kornbluth, MIT Corp Chair, Mark Gorenberg
Dear Dr. Kornbluth and Mr. Gorenberg,
The US House of Representatives is deeply concerned by ongoing and pervasive acts of antisemitic
harassment and intimidation at the Massachusetts Institute of Technology (MIT). Failing to act decisively to ensure a safe learning environment for all students would be a grave dereliction of your responsibilities as President of MIT and Chair of the MIT Corporation.
This Congress will not stand idly by and allow an environment hostile to Jewish students to persist. The House believes that your institution is in violation of Title VI of the Civil Rights Act, and the inability or
unwillingness to rectify this violation through action requires accountability.
Postsecondary education is a unique opportunity for students to learn and have their ideas and beliefs challenged. However, universities receiving hundreds of millions of federal funds annually have denied
students that opportunity and have been hijacked to become venues for the promotion of terrorism, antisemitic harassment and intimidation, unlawful encampments, and in some cases, assaults and riots.
The House of Representatives will not countenance the use of federal funds to indoctrinate students into hateful, antisemitic, anti-American supporters of terrorism. Investigations into campus antisemitism by the Committee on Education and the Workforce and the Committee on Ways and Means have been expanded into a Congress-wide probe across all relevant jurisdictions to address this national crisis. The undersigned Committees will conduct oversight into the use of federal funds at MIT and its learning environment under authorities granted to each Committee.
• The Committee on Education and the Workforce has been investigating your institution since December 7, 2023. The Committee has broad jurisdiction over postsecondary education, including its compliance with Title VI of the Civil Rights Act, campus safety concerns over disruptions to the learning environment, and the awarding of federal student aid under the Higher Education Act.
• The Committee on Oversight and Accountability is investigating the sources of funding and other support flowing to groups espousing pro-Hamas propaganda and engaged in antisemitic harassment and intimidation of students. The Committee on Oversight and Accountability is the principal oversight committee of the US House of Representatives and has broad authority to investigate “any matter” at “any time” under House Rule X.
• The Committee on Ways and Means has been investigating several universities since November 15, 2023, when the Committee held a hearing entitled From Ivory Towers to Dark Corners: Investigating the Nexus Between Antisemitism, Tax-Exempt Universities, and Terror Financing. The Committee followed the hearing with letters to those institutions on January 10, 202
Model Attribute Check Company Auto PropertyCeline George
In Odoo, the multi-company feature allows you to manage multiple companies within a single Odoo database instance. Each company can have its own configurations while still sharing common resources such as products, customers, and suppliers.
Embracing GenAI - A Strategic ImperativePeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
1. IST-2008 , Port-Elizabeth 7-10 Oct. 2008, South Africa
RECENT ADVANCES IN TECHNETIUM
ENVIRONMENTALLY FOCUSED
STUDIES
KONSTANTIN E. GERMAN
RUSSIAN ACADEMY OF SCIENCES
A.N. FRUMKIN INSTITUTE OF PHYSICAL
CHEMISTRY AND ELECTROCHEMISTRY
31/4 Leninsky prospect, Moscow , 119991, RUSSIA, Fax: 7-495- 335-17-78
2. 2008 – The Year of Tc
Plan of presentation
Tc in the environments – sources,
history and modern trends.
Tc in acidic and basic HLW.
Different methods of Tc HLW
treatment (insoluble residues, liquid
wastes discharcges, in-tank
storage, vitrification, plants
decomissioning, transmutation
projects )
Chemical species of Tc in waste
and environment
Physico-chemical aspects of Tc
(colloids and nanoparticles)
3. Saying “Tc” here we mean Tc-
99g
β-emitter (T½ = 2*105 y) accumulating with ~6% yeild by
U, Np or Pu fission = 1kg/t-U
Tc concentration in reprocessing solutions ~ 5-80 mg/L
Oxydation states: 0, +1, + 2, +2.5, +3, +4 , +5, +6, +7
Insoluble ε-phases = Tc metal
Volatile as:
Tc2O7, HTcO4 at T>100oC
TcO2 and Tc-metal (T>350oC+O2);
MTcO4 for M = Na, K, Cs atT>600oC = vitrification?
In WATER : Extrimly high migration rate : TcO4-
4. Technetium in the environment
in 1986, NEA_TDB –RARD in 1999
An exceptional issue of “Technetium in the environment” in 1986 although made of
independent parts was a complete presentation of all the pre-Chernobyl ideas and
results [1]. 13 years later an excellent review of NEA-TDB summed up the chemical
thermodynamics of Tc [2]. Time passed being characterized with the controversy of
nuclear industry present and future status, drastic for Tc-99 originating mostly as the
uranium fission product. The definite stop in nuclear development would fix the further
accumulation but now is clearly not the case and we appreciate the authors were
continuing efforts in Tc environmentally focused sciences. Several main directions
could be drawn out: firstly those dealing with already accumulated Tc [3-5], then,
focused on the construction of the migration barriers at the depositories [6-9] and
finally examining the Tc in vitrification. The understanding of Tc interaction with
microbial extremofils was importantly advanced [10-11]. The review is devoted to these
and numerous other results of environmental importance.
“Technetium in the Environment” (Proc. CEC-RPP – SERE CEA Seminar - Cadarache, 1984), Eds.:
G. Desmet and C. Myttenaere, Elsevier Publishers, L&N-Y. (1986).
Rard J.A., Rand M.H., Anderegg G., Wanner H., Chemical thermodynamic of technetium. Eds.
Sandino Amalia M., Osthols E. NEA (1999) Elsiever Publ. Amsterdam.
5. Technogenic sources of Tc to the
environments
Accumulation of 99Тс in nuclear industry = 8 ton/year
Discharge sources ofTc:
Explsions in atmosphere 180 TBq (Tera=1012) = 490 kg Тс
Chernobyl accident = 82 kg
NPP 1МBq /year 1000 МВт (электр.), т.е. :
В 2000 году все АЭС мира выделили ≈ 350 МБк Тс = 160 г
Заводы по переработке обл. топлива ≈ 10% от выбросов ЯТЦ
Завод Селафилд в Ирландское море
1952-1986 гг : 770 ТБк Тс = 1200 кг Тс
Завод мыс Аг (Франция) 1966 – 86 гг : 70 ТБк Тс = 100 кг Тс
Заводы изотопного обогащения U: 90% от выбросов ЯТЦ ≈ 4.1010
Бк Тс/год = 4,5 кг/год Тс
(Газодиффузионный завод в ОАК РИДЖ: 1975-82 гг. 5-30 Ки Тс =
0.3 - 2 кг Тс/год, 1982-1989 гг. 0.02 – 0.03 кг Тс/год, 1990 – 0.2 кг, 1992
– 1 кг в связи с началом демонтажа оборудования)
6. Different approaches to handling
the Tc-radwastes
Dilution in natural waters (only two isotopes β− 3H and
99
Tc) (UK, Russia -hystoric)
Underground injection HLW, MLW (Tomsk, Krasnoyarsk,
Dimitrovgrad)
Tank farms storage (military wastes, historic wastes)
Vitrification of histric wastes, witrification of raffinates
Metal forms
New venture forms
Separation and storage
Separation ant transmutation
7. The 1995-2005 years were Тс marked by severe
confrontation of Norwegian “greens” with Sellafield
authorities for B205-MAGNOX
discharges into the Irish sea - 180 kg-Тс/year
EARP
Тс-to-sea standard for Sellafield
B211 = 10 HLW tanks
( B205 + EARP-B211 + THORP ) 1050 cub. m each :
– 1995-2000 - 200 ТBq-Тс 5 tanks for “MAC”
– 2000-2003 - 90 ТBk-Тс 2 tanks– sludges
– TPPBr - April 23-24 - 2003 2 tanks - THORP
1 – empty in 2003
8. Pollution of the North sea, caused by
Sellafield, UK)
Тс content
In the samples collected in 1999 - 2001
water = 0.01- 0.07 Bq/L
algae = 510 Bq/kg ( ! )
lobsters = 33 - 42 Бк/кг ( ! )
(acc. to Bellona, Norvege)
Risks of refused distribution of Norvege sea-foods
9. Tc discharges in 2002-2005
The sum of total-beta activity (excluding tritium) from all
nuclear installations has fallen significantly over the
past 15 years. Total emissions are dominated by
discharges from the nuclear fuel plant at
Springfields and to a lesser extent the reprocessing
plant at Sellafield. The two installations together
contribute approximately 98 % of the overall
discharges. The high, but decreasing total-beta
discharges from Sellafield are mainly attributable to
the radionuclide Technetium-99. The reduction of
Sellafield’s total-beta discharges from 2002 to 2005
is a result of the significant reduction in
Technetium-99 discharges, due to the vitrification
process, since 1994 for oxide fuels and 2003, for
magnox fuels. Discharge of Tc-99 to sea (primarily
from treatment of stored Magnox wastes) has been
reduced between 1994 and 2005.
The total beta discharges from Sellafield (2002: 112
TBq, 2003: 83 TBq, 2004: 73 TBq, 2005: 43 TBq)
were previously mainly attributable to the
radionuclide Technetium-99 (2002: 85 TBq, 2003:
37 TBq, 2004 14 TBq, 2005: 6,7 TBq ), for which
abatement technology was installed in 2004. The
reduction of Sellafield’s total beta discharges in
2005 is due to the reduction of Technetium-99
(2004 14 TBq, 2005: 6,7 TBq),
10. Tc releases in Europe
Mayak
Karachay lake
VVER
3*10-2
For other European facilities the annual
Tc release is negligible
11. Tc behavior during the
underground HLW storage
Pretreatment : рН +
complexones + . . .
Ingection into the sandy levels
– collectors
Migration control
………………………………………………………. . .
Tc sorption at the minerals and
rocks was studied before
Main conclusions
Тс(VII) has high migration
Guerman K.E., Kosareva I.M., Peretroukhin V.F., mobility
Savushkina M.K., Egorov N.N., Kudryavtsev E.,
Revenko Yu.A. ICEM'95. V.1. Cross-cutting Issues Тс(IV) may form both immobile
and management of high-level waste and spent fuel.
(Eds.: S.Slate, Feizollahi, C.Creer), NY, 1995, p. 713 – 722 .
TcO2 and mobile complexes
12. Tc speciation in simulated radioactive wastes conditionned
for the underground injections (1980-88, 1994, 2000)
10
5
4
3
experiment
fit
TcO4- - is highly migrative
Radiolyses in presence of
Fourier Transform Magnitude
0
k 3 χ (k)
2
organic components lead to
-5
1
-10
the reduction of Тс(VII) to
0
4 6 8 10 12 14 0 1 2 3 4 5
-1
k (Å ) R + ∆ (Å)
EXAFS ROBL_ESRF Tc(V, IV, III)
Acetate complexes Тс(V, IV,
III) exist but the data are
scattered and the structure
not systematically studied
Acetate complexes of Тс(III)
could co-exist withTc(VII) .
13. Russians experience of Tc separation and
conversion (decl. avail.for CEA France 1994-1997)
Spitsyn V.I., Kuzina A.F., Prokopchuk Yu. Z., Chepurkov G.Ya. , German K.E.,
Oblova A.A.,Kryuchcov S.V. Preparation of technetium metal by thermal
decomposition of tetrabutylammonium pertechnetate in inert gas atmosphere.
Report IPCAS, N-P-2907, 1983.
Spitsyn V.I., Kuzina A.F., Prokopchuk Yu.Z., Chepurkov G.Ya., German K.E., Oblova
A.A., Kryuchcov S.V., Dzekun E.G., Sokhina L.P. Precipitation technology for
technetium separation from radioactive wastes. Report Mayak/IPCAS- 1984.
Spitsyn V.I., Kuzina A.F., Prokopchuk Yu.Z., Chepurkov G.Ya., German K.E., Oblova
A.A., Kryuchcov S.V., Tzarenko A.F., Akopov G.A., Krinitsyn A., Kapitonov V.I.,
Galkin A.,Maksimenko A., Berezuk N., Mezentsev V.I. Technology of technetium
recovery from radwastes.Report Mayak /IPCAS/ Khlopin Radievy.Inst.,1985, N P-
3171. 32 p.
Spitsyn V.I., Kuzina A.F., Prokopchuk Yu.Z., Chepurkov G.Ya., Guerman K.E.,
Oblova A.A.,Kryuchcov S.V., Kapitonov V.I., Mezentsev V.I. Improuvment of
anion exchange technetium recovery from radwastes using TBP as eluent.
Report Mayak -IPC AS. 1985, N P-3066 , 82 P.
German K.E., Kuzina A.F., Spitsyn V.I. Patent: Method of technetium carbide
preparation. USSR. Patent No 1258016, 1986.2
14. Russian approach to Tc separation in PUREX included (1980-1986):
extraction at the first extraction stage, back extraction at the U-Pu
separation stage, anion-exchange separation at QuatPhosBase AER,
purification at VP-1AP-AER, denitrification with formic acid or H 2O-SH,
precipitation of KTcO4 or R4NTcO4 and its conversion to metal Tc
Association
MTcO4 Solubility in Density constant in Conversion to metal:
M= water at 25°C g/ml water, L/M Search for the
Me4N+ 0.135 ± 0.005 1,67 - conditions (Ar-6%H2, gaz
0.096 [8]
(2.5 ± 0.7) x 10-2
product evaquation,
Et4N+ 1,34 -
1.24 x 10-2 at 20°C
(8.7 ±0.2) x 10 -3
Products - volatile and
Pr4N+ 7.8 x 10-3 [8] 1,26 2,6 ± 0,4 solid,
(4.3 ± 0.20) x 10-3
Bu4N+
4.2 x 10-3 at 20°C
1,17 15 ± 3 Russ.Inorg. Chem-2002
Pent4N+ (7.9 ± 0.2) x 10-4 1,12 27 ± 5
-47-No5
Hex4N+ (7.1 ± 0.5) x 10-5 1,07 40 ± 5
Hept4N+ (8.8 ± 0.8) x 10-6 1,03 52 ± 5
p[(C4H9)4N]OH (aqueouse) ↔ [(C4H9)4NOH]p (aqueouse) (8)
[(C4H9)4N] (aqueouse) + TcO4 (aqueouse) ↔ [(C4H9)4N]TcO4 (solide)
+ -
(9)
[(C4H9)4NOH]p (aqueouse) + TcO4 (aqueouse) ↔ [(C4H9)4NOH]p-1TcO4 (aqueouse) + OH (10)
- -
HTcO4 ↔ H+ +TcO4- (TcKa)
Tc
Ka/( TcKa + [H+]) = [TcO4-] /([TcO4-]+ [HTcO4]) = [TcO4-] /[Tc]tot
The TcKa was found equl to 4.02 M which is in very good agreement with [ [i]]
[i]
Ashley K.R., Ball J. R. Solvent extraction and ion exchange, 1994, 12(2), p.239-259.
15. Co-precipitation of Tc(VII) with Bu4NReO4
from 100 ml 1.0 M NaOH, [ TcO4-] = 5*10-4 M, [ Bu4N+]
= 0.005 - 0.02 M, reagent = 0.1M NH4ReO4
Tc fraction
remained
in the solution 0,02M Bu4N
1 0,01M Bu4N
0.005M Bu4N
0.8
0.6
∆ V= +3%
0.4
0.2
0
100 102 104 106 108 110
Total volume, %
17. Tc under HAW vitrification conditions
No stable Tc silicates were found before – but now we
know about Tc sodalite although losing in structure
stability to cancrinite in presence of common nitrate
Pertechnetates are volatile at temp. > 600oC
Reduced Tc valence forms –
Tc(IV) no interaction with silicates
Tc(0) no interaction with silicates
Tc separation before HAW vitrification is preferable
18. Methods for Tc separation from alkaline and
neutral solutions
Not a problem compared to acidic, quite efficient
are several methods used in Russia in 1980-85
EXTRACTION Chromatography
Ketones : Aceton, QuatPhosBase(KHL-Rad-
Methyl-ethyl-ketone,) Inst) +VP-1АP(IPCERAS)
ТPPBr/ТPAsBr/CCl4 (= RAILEX) for technology
Polyglicoles HPLC - DIONEX-AS11 (for
anallyt separation from
MoO4/I/Br/ClO4/TcO4)
solidex TPPBr (developed for HLW B205-MAGNOX)
- Not easy when Tc species is different from Tc(VII)
(Schroeder, 1996 - Hanford: treatment with S2O8 etc.
19. Properties of different reagents for Tc
separation by (co-) crystallization or solidex
technology
Table 4.1 Aqueous solubilities of technetium salts Тетрафениларсоний бромид
Pertechnetate cations Solubility at 25ºC, M (Трибалат, Кузина)
Cesium 1.60x10-2 Нитрон (Кузина)
Thallium 3.1x10-3
Tetrapropylammonium (8.7± 0.2)x10-3
Тетрафенилфосфоний
бромид (BNFL) (совместимы с
Tetrabutylammonium (4.3 ±0.2)x10-3 фосфатными стеклами)
4.2x10-3 at 20° C
-4 Тетраалкиламмоний бромид /
Tetrapentylammonium (7.9 ±0.2)x10
перренат (осадки совместимы с
Tetrahexylammonium (7.1 ±0.5)x10-5 боратными стеклами, метод
Tetraheptylammonium (8.8 ±0.8)x10-6 опробован в 1982-85 совм. с ПО
Triphenylguanidinium (3.9 ±0.3)x10-3 Маяк, в 1995-97 определены
Tetraphenylarsonium (4.0 ±0.2)x10-4 оптимальные осадители,
которые рекомендованы КАЭ
Франции и ДЭ США)
Some of these regents were also used for
•Tc-Ion-selective electrode construction
•Fiber sorbents production
20. The SRS waste volumes (Table 2.4 of "Integrated Database Report - 1993: S.Spent
Fuel and Radioactive Waste Inventories, Projections, and Characteristics,”] Tc-99
quantities (Table 2.11), and Tc-99 concentrations calculated from these data
Isolation Valve
Capped
Tank Equipment Risers (typ) Service Line (e.g. steam, air)
(e.g. slurry pump)
Grout fill
Formwork
2000# grout (typ)
Underground
line
(valve closed) Diversion Box
CLSM
Underground line
(line capped)
Reducing Grout
SRS TYPE IV HIGH LEVEL WASTE TANK
Volume, Tc-99, Ci [Tc-99], [Tc], 10 6 Kd
liters Ci/liter g/liter
total
Liquid 61.4 1.68E+04 2.74E-03 0.162 -
Sludge 13.9 1.14E+04 8.20E-03 0.483 3
Salt Cake 53.8 2.78E+03 5.17E-04 0.0305 0.2
Overall waste 129.1 3.098E+04 2.40E-03 0.141 -
Question to be answered : Which components absorb Tc with Kd
higher than 3 and are resistant to leaching?
21. Tc concentrations found in
99
various tank sludges at SRS
[Tc-99],
The discovery of relatively Tank mCi/g dried Reference
high 99 Tc concentrations Number solids
in inorganic mineral 17 0.462 d'Entremont et
sludge heels taken from al. 1997
some tanks at the US- 20, white 0.34 d'Entremont and
DOE Savannah River Site solids Hester 1996
(SRS) has prompted 20, brown 0.94 d'Entremont and
investigations of Tc solids Hester 1996
uptake from alkaline 42 0.22 Hay 1999
highly active waste (HAW)
51 0.21 Hay 1999
by solid adsorbents
8 0.22 Hay 1999
11 0.34 Hay 1999
22. Sludge components as carriers
for Tc(VII) and Tc(IV)
S O L ID S L U D G E C O M P O N E N T S
W H IT E S O L ID S B R O W N S O L ID S
A L U M IN O S IL IC A T E S M E T A L H Y D R O X ID E S
C A N C R IN IT E (F e , C r, M n )(O )(O H )
S O D A L IT E
. C R Y O L IT E . . P L A T IN U M G R O U P .
N a 3 A lF 6 M E T A L S
R h , R u , P d
. S O D IU M O X A L A T E .
N a 2 C 2 O 4
TiO2 was also tested
23. Study of Tc uptake with Aluminosilicates
under oxidizing conditions at 70-130oC
Literature data have demonstrated the possibility of
ClO4- and MnO4- co-crystallisaton with aluminosilicates :
purple Na8[AlSiO4]6(MnO4)2 (Weller,1999 etc.)
OUR EXPERIMENTS on TcO4- (reaction: NaAlO2+Na2SiO3+NaOH)
Solution Formed solid Kd
TcO4- is too large
10-3-10-5M Tc and therefore it is
0.2-5M NaOH Cancrinite less 1
0.5-5 M NaNO3
excluded from the
aluminosilicate
10-3-10-5M Tc structure in both
0.2-5M NaOH Sodalite less 1
NaNO3 free
cancrinite and
sodalite
24. Case of Aluminosilicates formed
in concentrated Tc(VII) solution
[Tc] = 0.2 M Fig. 1. NMR-99Tc spectrum of the aluminosilicate containing
in NaNO3 solutions - cancrinite 57 mg-Tc/kg. Tc spectrum presents evidence for -30 ppm shift
characteristic of coordinated pertechnetate
in NaNO3-free solutions - sodalite
Although NMR spectrum presented
shift typical for coordinated Tc(VII)
its concentration is very low
Dissolution in NaHF2 and LSC has
shown : [Tc] in solid cancrinite was
57 mg/kg ~ 100 times less than in
initial solution
Tc is excluded from the
aluminosilicate structure
25. Study of Tc uptake with Aluminosilicates under
reducing conditions
(0.2M N2H5Cl, 1M NaNO3, T = 800С, t = 3 d)
Precipitation of Leaching conditions:
cancrinite↓
Leaching T, Leaching yield , Tc, %
NaOH Tc yield, agent: o
C
3 1 day 10 days
M %
hour
2.0 18.9 1M NaOH 20 0.8 1 3.7
4.0 32 2M NaOH 20 0.8 1.2 2.0
2.0 25.2 0.1M NaOH + 60 25 26.9 27
0.25 M H2O2
2.0 18.9 0.1M NaOH + 18 4 6.9 7
0.5 H2O2
4.0 32 0.1M NaOH + 18 6.5 6.9 11
0.5 H2O2
Under reducing conditions Tc uptake is important
Tc(IV) in aluminosilicates is resistant to leaching
26. Study of Tc(VII) sorption
by crystalline TiO2
under oxidizing conditions
Tc(VII) was sorbed by TiO2
from neutral solution
with Kd = 30 ml/g.
However, the Kd at pH=10
was only 3.3 ml/g Among the
No affinity to Tc(VII) was minerals tested for
noted for TiO2 at pH=12 Tc(VII) uptake,
and higher . high-density TiO2
MST and was the most
Silicotitanates yet not efficient
27. Study of Tc uptake with
Na oxalate under
oxidizing and reducing conditions
NaOH + H2C2O4 = Na2C2O4
X-ray diffraction tests :
the precipitate is
sodium oxalate Na2C2O4
(PDF#20-1149)
Tc(VII) is excluded from the Na oxalate structure
under oxidizing conditions (Kd = 1-2)
Under reducing conditions Tc(IV) forms a separate
TcO2*1.6H2O phase - no interaction between Tc
hydroxide and Na oxalate were detected
Tc precipitate is not resistant to leaching with 0.1 N
NaNO2
28. Study of Tc uptake with
Cryolite Na3AlF6 under
oxidizing and reducing conditions
6F-+NaAlO2+Na2CO3
X-ray diffraction tests :
the precipitate is cryolite Na 3 AlF 6
Reduced Tc : Oxidizing
conditions:
17-35% of Tc(IV) as
TcCl62- is co- Kd is less 1
precipitated with
cryolite Tc(VII) is excluded
N2H5NO3 inhibits co- from cryolite
structure
precipitation
29. Study of Tc(IV) uptake
with Cryolite Na3AlF6
under reducing conditions
[NH4F] [Na2CO3] in [N2H5NO3], in Tc(IV)
No initial, final solution, final solution, uptake,
M M M %
1 2,0 0,6 - 20
2 2.5 0.6 - 23
3 3.0 0,6 - 26
4 4,0 0.6 - 28
5 6,0 0,6 - 35
8 2,0 0,4 - 25
9 2,0 0,8 - 17
10 2,0 0,6 0,1 0
• Tc(IV) is added as Na 2 TcCl 6 to ( NH4F+NaAlO2)
solution
• No additional reducing agent in exp. No 1-9
• Leaching test were impossible to quantify
30. Study of Tc(IV) uptake with
FeOOH under reducing conditions
Reducing agent: 0.02M FeSO4, T = 600С, time = 3 h
Precipitate : FeOOH/Fe2O3
Precipitation test: Leaching test (t=18 oC, d = days):
NaOH Tc in solid Leaching Leaching yield ,Tc, %
M phase, % agent: 1 d 10 d 29 d 105d
0.6 97 0.1M NaOH 1.0 9.8 14.9 24
2.0 88.0 1M NaOH 2.9 16.5 40.2 58
4.0 90 2M NaOH 0.8 2 3 8.2
Though Tc adsorbed better on iron hydroxides from 0.5–2.0 M NaOH
than from 3.0-4.0 M NaOH, the precipitates formed at lower NaOH
concentration were more easily leached by the NaOH leachant
Tc leaching with H2O2 was 20 % and with Na2S2O8 was70-100% in 100
days
31. Study of Tc(IV) uptake with
MnOOH under reducing conditions
Reaction NaOH + Na2MnO4+ N2H5OH= MnOOH
X-ray diffraction tests : the freshly precipitated
solid was Mn2O3 , the aged precipitate was
manganite MnOOH (PDF#18-805)
MnOOH precipitation MnOOH leaching to 0.1 NaOH (1,3,4) and Na2S2O8(2)
12
1) Mn/Al=1/10
90 2) Mn/Al=1/40
10
3)Mn/Al=1/10
75
Tc uptake by precipitate, %
8 4) Mn/Al=1/40
Leached Tc, %
60
Mn/Al=1/10 6
45
30 Mn/Al=1/40 4
15 2
0
0
0 5 10 15 20 25 30
0 2 4 6 8 10 12
Time,d Time. d
Manganese(III) oxides were effective Tc carriers and
underwent chemical transformations on ageing that increased
leaching resistance to most agents.
32. Boehmite sorbs perrhenate and pertechnetate
By Peng-Chu Zhang*, James L. Krumhansl and Patrick V. Brady
Sandia National Laboratories, Albuquerque, USA
Radiochim. Acta 88, 3692373 (2000)
(a) Al(OH)3 - Aluminum hydroxide - gibbsite ;
(b) Boehmite [AlO(OH)] -aluminum oxyhydroxide
(c) Al2O3 aluminum oxide - corund
Boehmite and Al-oxyhydroxide gels sorb ReO4 a non-radioactive
analogue of TcO4 from NaNO3 solutions.Sorption appears to be
substantially electrostatic (though there appears to be a specific
preference for ReO4 over NO3 and is most effective at pH , 8.
Measured Kd’s lie between 5 and 105 ml g-1, depending on the solid,
pH, and ionic strength. ReO4 and TcO4 are both partially removed
from high pH Hanford-type acid waste simulants upon neutralization
and formation of Al-rich sludges. It was proposed that sequestration of
Tc by boehmite limits dissolved Tc levels in the near and sub-surface
environment and for that purpose boehmite might be relied on as a
backfill, or reactive barrier, to limit environmental transport of Tc.
How Mo-Tc generators could do work being made of Al oxide - oxyhydroxide ???
33. Tc(VII) + S2-
Kinetics of the reaction of pertechnetate with sulfide
in 0.3M Na S solution at 22oC
2
1.0
0.9
0.8
0.7
Convertion degree
0.6
0.5
[Tc], *104M
0.4
Tc2.66
0.3 Tc1.9
Tc1.52
0.2
Tc1.14
Tc0.57
0.1
0.0
0 2 4 6 8 10 12 14 16 18 20 22 24
Time, min
34. Separation of Tc2S7 colloides from Na2S solution by
Microfilterfuge (RAININ Instr. Co) with ultrafiltration
membranes - 30000 NMWL
Tc2S7 ultrafiltration
[Na2S]
Formation of colloides Tc2S7
0.0007
0.46M is complète in 50 hours
0.0006
0.0005
0.33M under these conditions
0.2M
C(Tc), M/L
0.0004
0.13M
0.0003
0.0002
0.066M [Tc] in the solutions at
0.0001
0.033M
times from 50 to 150 hours
0.02M
0
0 25 50 75 100 125 150 175 200
corresponds to true
TIME, H solubility of Tc2S7
Solubility Tc2S7 in Na2S solutions
0.00035
0.0003
C(Tc) = -9E-05Ln[Na2S] - 2E-05
0.00025 R2 = 0.9917
C(Tc), M/L
0.0002
0.00015
0.0001
0.00005
0
0 0.1 0.2 0.3 0.4 0.5
[Na2S], M/L
35. The reduction of Tc(VII) to Tc(V,IV,III ) by
abiotic and biotic processes
The reduction of Tc(VII) to Tc(IV) by abiotic and biotic processes has recently
been the subject of extensive studies because it has a significant effect on
the mobility of technetium in waste streams, vadose zones, sediments, and
groundwater. These reaction processes are the basis for certain
remediationtechnologies such as permeable barriers composed of zero-
valent iron particles (i.e., as metallic iron) or sodium-dithionite reduced soils,
which are being tested for immobilization of groundwater contaminants.
36. Microbial reduction of Tc(VII)
Microbial reduction of Tc(VII) has been suggested as a potential mechanism
for removing technetium from contaminated groundwaters and waste
streams (e.g., Lovley 1993, 1995, Lyalikova,German et all. 1994).
Certain dissimilatory metal reducing bacteria and sulfate reducing bacteria
have been determined to be capable of coupling the oxidation of organic
carbon or hydrogen to the reduction of Tc(VII) to Tc(IV)
(Lyakikova,German,Khizhnyak Peretrukhin 1994 , 1998, Gavrilov –German
2007 and Lloyd and Macaskie 1996; Lloyd et al. 1997, 1998, 1999, 2000a,b;
Wildung et al. 2000; Fredrickson et al. 2000).
37. Transmutation
Tc-Ru acidic and pyrochemical
solubilization problem
N. Schroeder approach : homogeneous transmutation