Entfernung von Uran aus Trinkwasser an granuliertem Eisenhydroxid

Chemie.DE News-Center: Wissenschaftler der TU Berlin beseitigen Uranspuren im Trinkwasser mithilfe neuartiger Adsorptionstechniken

Problematisch ist die hohe chemische Toxizität von gelösten Uranverbindungen.

'Noch gibt es keinen gesetzlichen Grenzwert, aber die Weltgesundheitsorganisation (WHO) hat 2004 einen Richtwert von 15 Mikrogramm pro Liter festgesetzt, der nicht überschritten werden sollte. In Teilen Deutschlands werden aber deutlich höhere Werte gefunden (bis 100 Mikrogramm pro Liter). Am Fachgebiet Wasserreinhaltung des Instituts für Technischen Umweltschutz der TU Berlin haben sich Wissenschaftler unter der Projektleitung von Prof. Dr. Martin Jekel dieses Problems angenommen und suchen nach Möglichkeiten, Uranspuren aus Trinkwasser zu entfernen.'
'Die Schwierigkeit sowohl bei der Uranbeseitigung als auch der Urananalytik ist die komplexe Speziation des Metallions in wässrigen Lösungen. Je nach pH-Wert, dem Salzgehalt sowie der Anwesenheit anderer Wasserinhaltsstoffe bilden sich unterschiedliche Uranspezies (Uran(VI)-ionen, Carbonate, Oxide, Phosphate usw.), die an Metalloxiden völlig unterschiedlich adsorbieren.'

Study shows UV filters may disrupt hormone production

Study shows UV filters may disrupt hormone production

comment on EPA Press Release Biogenesis Soil washing Technology

Environmental Protection Agency - EPA Press Release: Technology Turns Contaminated Sediment into Useful Product; Environmental Headache Can Become Valuable Product

Through the Bioremediation Discussion Group - Bioremediationgroup.org

Biogenesis Soil washing process is far from being new. I knew about it over 10 years.

No doubt this is a useful technology, however, it has its limitations due to basic physico-chemical principles. It is especially suitable for removal of petroleum related contaminants if the soil does not contain a to high fraction of fines.

For higher PAH contamination it can only reduce the contaminant load, however, it will never be able to meet more stringent remediation targets.

'The BioGenesis Sediment Washing Technology strips contaminants, such as PCBs, dioxins' - this is surely far from being realistic.

Pflanzenschutzmittelrueckstaende in rund 60 Prozent der Lebensmittel

Veröffentlichung idw (Informationsdienst Wissenschaft) /BVL (Bundesamt für Verbraucherschutz und Lebensmittelsicherheit)

Der Anteil von Lebensmitteln, bei denen Rueckstaende von Pflanzenschutzmitteln festgestellt wurden, die die gesetzlichen Hoechstmengen nicht ueberschritten, lag im Jahr 2004 bei rund 52 Prozent. Bei 7,4 Prozent der Proben wurden die gesetzlichen Hoechstmengen nicht eingehalten. In rund 40 Prozent der untersuchten Proben wurden keine Rueckstaende von Pflanzenschutzmitteln nachgewiesen. Dies sind Ergebnisse der "Nationalen Berichterstattung Pflanzenschutzmittelrueckstaende", die das Bundesamt fuer Verbraucherschutz und Lebensmittelsicherheit (BVL) auf der Grundlage von Daten der Bundeslaender heute in Bonn veroeffentlicht hat.

Zu den am staerksten belasteten Obst- und Gemuesearten gehoeren Rucola, Paprika, Johannisbeere, Tafeltraube und Gurke. Keine Ueberschreitungen der Hoechstmengen wurden hingegen in Saeuglings- und Kleinkindernahrung, Bananen, Broccoli, Pilzen, Spargel und Zwiebeln festgestellt. Grundnahrungsmittel wie Getreide und Kartoffeln waren nur geringfuegig belastet. Selten kam es bei Kiwis, Orangen, Zitronen, Karotten und Tomaten zu Hoechstmengenueberschreitungen.

.......

In 36,5 Prozent aller Proben wurde mehr als ein Rueckstand gefunden. ............
Die Ueberschreitung von Rueckstandshoechstmengen ist nicht mit einer akuten Gefaehrdung der Gesundheit der Verbraucher gleichzusetzen. Bei Ueberschreitungen der Hoechstmengen schaetzt die zustaendige Ueberwachungsbehoerde das toxikologische Risiko ab. Bei 16 Proben konnte 2004 auf Grund deutlicher Ueberschreitungen ein gesundheitliches Risiko fuer den Verbraucher nicht ausgeschlossen werden. In diesen Faellen hat das BVL die fuer die Lebensmittelueberwachung zustaendigen UEberwachungsbehoerden der Bundeslaender sowie die EU-Kommission ueber das Europaeische Schnellwarnsystem informiert.

Papers at 5th World Congress on Particle Technology

5th World Congress on Particle Technology - WCPT5 - Orlando 2006

Use of multisample analytical centrifugation for evaluation of separation of fine particle slurries in the centrifugal field

T. Sobisch, D. Lerche, T. Detloff

Dispersion Stability & Particle Analysis, L.U.M. GmbH

Rudower Chaussee 31, 12489 Berlin, Germany,

info@lum-gmbh.de, www.lum-gmbh.com

Unit processes using centrifugal fields are often applied for separation, deliquoring and classification of fine grained materials. Modelling of these processes requires information about the separation behaviour of the suspensions to be processed. To this end direct measurements in centrifuges are obligatory. Moreover, these measurements have to gather kinetic information as function of the processing conditions, particle interaction and particle concentration.

The separation behaviour of quartz (stable dispersions) and limestone suspensions (moderately and strongly flocculated) was investigated as function of solid concentration and centrifugal acceleration using a multisample analytical photocentrifuge. The new multisample approach uses the STEP-technology. Space and time resolved extinction profiles quantify the alteration of particle concentration, the velocity distribution of particles and packing behaviour during centrifugation. Particle interactions are characterized by the packing density determined under defined conditions and by its variations under alternating centrifugal load.

Multisample analytical batch centrifugation with optical detection proved to be a versatile tool for the characterization of the separation of fine grained materials. This holds for information on the type of sedimentation behaviour (free sedimentation of individual particles, hindered settling, zone settling) on the sedimentation velocity distribution inside the centrate and on the packing, compression and elasticity behaviour, on the nature of particle interactions and the degree of flocculation as well.

The results of multisample analytical centrifugation with optical detection were in good agreement with the results derived by other methods (velocity distribution determined by manometric detection and average packing density obtained during compression in a disc centrifuge).

Characterization of interparticle forces in aqueous and nonaqueous dispersions using multisample analytical centrifugation

T. Sobisch, D. Lerche

info@lum-gmbh.de, www.lum-gmbh.com

The behaviour of dispersions in liquid media, i.e. dispersion stability, flow, separation and packing behaviour, is determined by the nature and degree of interparticle forces. This is of fundamental importance for their application in diverse fields such as nanomaterials, coating, paper making, ceramics, sludge dewatering, to name just a few.

The present work reports on the use of multisample analytical centrifugation for investigation of the packing and compression behaviour to characterize the colloidal stability and microstructure in aqueous and nonaqueous dispersed systems.

Packing density, obtained after compression, is related to the total interparticle potential energy. By using different additives interaction between particles can be shifted from nearly hard sphere behaviour to strong attraction which results in flocculated systems. Additional information could be obtained about the strength and elasticity of particle networks by analysing the relative change in sediment volume after increasing/decreasing the excess pressure in multiple cycles.

The multisample technique applied implies the potential for more systematic studies for targeted colloidal stability.

The new multisample approach uses the STEP-technology. Space and time resolved extinction profiles quantify the alteration of particle concentration and packing behaviour during centrifugation without the need for sample dilution. The latter is a necessary prerequisite for ensuring that the liquid dispersions maintain their original properties.

The paper further covers the influence of the nature of interparticle forces on segregation and deliquoring of common polydisperse fine particle slurries in the centrifugal field.

KEYWORDS: Multisample Analytical Centrifugation, Interparticle Forces, Particle Interactions, Packing Behaviour, Dispersion Stability, Consolidation, Compressibility

Characterization of liquid nanoparticle dispersions by multisample analytical centrifugation

Particle interaction, colloidal crystallization

T. Sobisch, D. Lerche

info@lum-gmbh.de, www.lum-gmbh.com

Reducing particle dimensions to nanoscale leads to qualitatively new properties. This holds also for liquid dispersions, which are the most often used form of application of nanoparticles.

For characterization of nanoparticle dispersions techniques are preferable, which avoid dilution, thus don’t modify dispersion properties. To this end multisample analytical centrifugation proved as an efficient tool.

The new multisample approach uses the STEP-technology. Space and time resolved extinction profiles quantify the alteration of particle concentration but also packing behaviour and phase separation during centrifugation.

Examples are presented for the detection of the presence of flocculation in nanoparticle suspensions, for examination of microgels and colloidal crystallization. The behaviour of microgels was characterized as function of centrifugal acceleration, temperature and concentration. Further, the effect of initial volume concentration and sediment pressure on the speed and extend of the crystallization process was studied.

KEYWORDS: Multisample Analytical Centrifugation, Nanoparticles, Microgels Interparticle Forces, Particle Interactions, Packing Behaviour, Colloidal Crystallization

PAH in clothing

mail from Joseph Mc Donald

I am hoping you may be able to answer a question that seems to have everyone staring into space. It appears we are all focused on what pollutants are in the air , water and soil but no one seems to know what happens to them when they come into contact with our clothing.

Living in a area where coal burning is still common practice for domestic heat and power generation it is quite common for clothing to be exposed to various levels of Coal soot and it's bi- products on a daily basis. ( just a note we burn oil but have many neighbors that burn coal and one of the power plants is 2 miles away) Seeing soot on the cars etc. is part of daily living and we always assumed once our clothes were machine washed with a brand name detergent any soot contamination would be removed. However approximately 15 months ago a family member became ill and it was determined PAH or heavy metal exposure were contributing factors. Since this individual worked in an office environment as did the rest of the family we frantically searched for the potential source and had various tests completed.

To our surprise we found various trace heavy metals and PAH evidence still present in freshly washed clothes which was shocking and the urine analysis for heavy metals on all three family members followed the same pattern, including a 13 year old. All clothes were also machine dried indoors. It appeared Sulfur, Barium, Beryllium, Thallium, Uranium, Magnesium, Strontium and Nickel for example were in the clothes after washing and also over the normal ranges in our bodies. Yet lead, mercury, etc were all perfect. We did not have the resources to do any extensive testing on PAHs but did find 1-oh-pyrene in urine ( benzene). I could not afford to have any further testing completed.

My question is has anyone completed any detailed testing in this area after removal of the tri sodium phosphates from the detergents to ensure no traces of PAH or heavy metals were being left behind. The detergent manufactures will not give anything other than a generic answer and I have tried them all. There are thousands of individuals that work in various heavy industry that are exposed to PAHs and heavy metals daily , those on the street levels of the larger cities, etc. who like us wash our clothes in the household machine assuming all of these potential toxins are being removed. But are they really or are we wearing a toxic patch.

From your experiences with PAHs / heavy metals over the years how would you say they should behave when on clothing and are exposed to a machine wash and modern detergent, would they stay in place since they do not dissolve in water, would they eventually break down on the clothing even though they are not being exposed to direct sunlight or microorganisms in soil. Would they ever break down in an indoor environment. Do they just sit there on the clothes until we eventually come into contact with them and absorb them.

Answer

Contaminants in clothes are an issue. There are also related investigations (at least determining contaminant levels). However, these are related to pesticide residues, heavy metals (black coloured clothes) and cancer causing dye compounds. We have here a monthly journal 'oekotest', which deals with issues like contaminations in various consumer products.
However, I would argue that PAH in clothes is not an issue of concern.

Points to consider

# PAH will not be removed by washing, only partly. However, the part easily available for further transport into the body will be removed.
# one should focus on the main routes of transport into the body - which is transport through the lungs (diesel particulates, road dust, tobacco smok, of course soot from coal burning).

That is uptake by routes other than clothes is far more likely!

Similar to contamination of soil, also in clothes only a part of the PAH is readily available for transport.
This is due to differences in physical properties (PAH group is a mixture of compounds with different solubilities, partition coefficients etc.) and differences in the nature of bonding and location inside the fibers. PAH located on the surface are very much more available for transport than PAH which have penetrated into the fibres.
By the way, phosphates are not an issue here. The main action of removing the contamination is due to surfactants. In detergents the phosphates have been replaced by other ingredients, which at least have similar positive effect on removal of PAH as the phosphates.

So there are essentially only two alternatives - move to a location in a pristine environment or raise the issue of environmental contamination.

I am very sorry about the health problems experienced in your family.