Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

The retention of transition metals

20.10.2003


The aim of this PhD is to study the retention of transition metals by humic substances. Transition metals are essential for life but, depending on their concentration in the environment, they can prove to be toxic and provoke serious environmental impact.



Humic substances are, on the other hand, macromolecules arising from the physical, chemical and microbiological transformation (humification) of biomolecules, explains Álvarez Puebla. Their importance is fundamental as they make up the most widespread an ubiquitous source of non-living organic material that nature knows. Approximately 80% of the total carbon in terrestrial media and 60% of the carbon dissolved in aquatic media are made up of humic substances.

Beyond their relevance for life, these substances have industrial applications for making absorbents of metal-poisoned sources. Being natural substances, their purification process is cheaper than the synthesis of any other absorbent and, moreover, due to their high operability, they absorb more than the absorbents used to date such as active charcoals or clays.


Mechanisms of retention

Humic substances have a great capacity for retaining transition metals, forming metalorganic complexes which cause these metals to be more or less available for plants and the plants pas to animals and these to humans.

Thus, Álvarez Puebla proposed a study of how the retention mechanisms operate in order to find out both the capacity and strength of retention a specific humic substance might have; i.e. how this metal-humic substance complex behaves after being subjected to different conditions.

To this end, copper, nickel and cobalt were chosen as all three are in the First Transition Series, are consecutive, are necessary for life, are quite common in industrial effluents, are very used and are very well parameterised for study by means of computer techniques.

Mathematical model for analysis

Álvarez Puebla drew up a mathematical model which enabled an interpretation of the interaction between metals and humic substances. This model considers the global process retention as a series of simple processes and, according to the author, provides good results and reveals a considerable selectivity of humic substances in order to retain the various metallic species as a function of pH and, to a lesser extent, of the concentration of the metal species in the solution.

Also, the theses held by other researchers, which have even been used as a basis for a United States legislative bill, argue that the transition metals may be liberated in alkaline soil, given that an insoluble hydroxide is formed which stays retained in the soil.

However, Álvarez Puebla has shown that humic substances, present in all soils, can mobilise the metal in question because they co-ordinate with it and make it soluble. On the metal mobilising with rain or river water, it can reach subterranean waters and return to the food chain, contaminating the environment.

All this research has been carried out both at a macroscopic level and a microscopic one, by means of various analysis techniques and mathematical and molecular modelling. In this way, the mechanisms of interaction of Co(II), Ni(II) and Cu(II) have been determined in a humic substance complex and its fractions, as a function of the metal concentration and pH of the medium.

Contact :
Iñaki Casado Redin
Nafarroako Unibertsitate Publikoa
inaki.casado@unavarra.es
(+34) 948 16 97 82

Iñaki Casado Redin | Basque research
Further information:
http://www.basqueresearch.com
http://www.unavarra.es

More articles from Life Sciences:

nachricht Repairing damaged hearts with self-healing heart cells
22.08.2017 | National University Health System

nachricht Biochemical 'fingerprints' reveal diabetes progression
22.08.2017 | Umea University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

Cholesterol-lowering drugs may fight infectious disease

22.08.2017 | Health and Medicine

Meter-sized single-crystal graphene growth becomes possible

22.08.2017 | Materials Sciences

Repairing damaged hearts with self-healing heart cells

22.08.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>