A new method for removing heavy metals tested in the port of Piombino
Iannelli: «The reclaimed sediments can then be conveniently reused as recovery materials on construction sites and road surfaces»
[2 Maggio 2024]
The University of Pisa has successfully tested a new method for the electrokinetic remediation of marine sediments, capable of removing the heavy metals present with an efficiency that is up to double that allowed by existing techniques.
«The results of this experiment on marine sediments taken from the port of Piombino are very encouraging. This optimization of the reclamation process is useful for reducing consumption, treatment times and waste. From the perspective of the circular economy, the reclaimed sediments can then be conveniently reused as recovery materials on construction sites and road surfaces”, explains Renato Iannelli of the Energy, systems, land and construction engineering of the Pisan University.
The results of the study carried out on samples dredged in the port of Piombino were published in the journal Heliyon: after 95 days of treatment, the innovative system allowed a significant reduction of chromium (48.80%), nickel (61.53%) , lead (63.30%), copper (72.84%) and zinc (56.30%).
«For the electrokinetic remediation of marine sediments – argues Iannelli – we have designed a particular hexagonal configuration of the matrix which has proven to be more efficient in the removal of heavy metals than the linear one usually used».
The electrokinetic reclamation of sediments occurs thanks to the migration of metals from cathodes to anodes up to the cathode well where they solubilize and are thus removed. The electrode configurations most used today have a square mesh, made up of rows of cathodes alternating with rows of anodes, in which, however, this migration slows down near the cathode, so much so as to require an increase in current and therefore greater energy consumption .
The hexagonal matrix designed at the University of Pisa, in which each cathode is surrounded by six anodes, solves this problem. In fact, by halving the number of cathodes compared to anodes, in the area where the slowing down of metal migration is observed in the traditional configuration, the doubled current facilitates the completion of the path.
