Back to results
US 2009/0257828 A1Published application
Method for reclaiming lands polluted by hexavalent chromium
OwnerFabio Longoniinventor
Life of this patent
Estimating the term…
Abstract
A procedure for the on-site reduction to a predetermined level of the concentration of hexavalent chromium in a saturated or unsaturated contaminated area or ground, in which an in-depth treatment of this area or ground is carried out with a predetermined quantity of a gaseous mixture consisting of hydrogen and another inert gas in order to chemically reduce the hexavalent chromium to a state of lower valence, in particular to the state of trivalent chromium.
Claims6
1:
- A procedure for the on-site reduction to a predetermined level of the concentration of hexavalent chromium in a saturated or unsaturated contaminated area or ground, comprised of the in-depth treatment of this area or ground with a predetermined quantity of a gaseous mixture consisting of hydrogen and another inert gas in order to chemically reduce the hexavalent chromium to a state of lower valence, in particular to the state of trivalent chromium.
2:
- A procedure according to claim 1, in which the hydrogen is present in the gaseous mixture at a percentage not greater than 10%.
3:
- A procedure according to claim 2, in which the percentage of hydrogen does not exceed 4%.
4:
- A procedure according to claim 1, which comprises the preparation of a network of shafts of different depths for the injection of the gaseous mixture in the polluted area or ground to be decontaminated.
5:
- A procedure according to claim 1, in which the inert gas used in the gaseous mixture is nitrogen.
6:
- A procedure according to claim 1, in which predetermined quantities of an oxalic acid based solution are injected at predetermined time intervals in order to complex the Cr(III) produced by the reduction of Cr(VI).