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 What Makes Stem Cells into Perfect Allrounders
27.06.2017 | Universität Zürich

nachricht Study shines light on brain cells that coordinate movement
26.06.2017 | University of Washington Health Sciences/UW Medicine

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Study shines light on brain cells that coordinate movement

26.06.2017 | Life Sciences

Smooth propagation of spin waves using gold

26.06.2017 | Physics and Astronomy

Switchable DNA mini-machines store information

26.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>