Degradation of obsolete DDT by Fenton oxidation with zero-valent iron

Abstract

We report in this paper the preliminary results obtained during degradation tests of obsolete DDT by Fenton oxidation with zero-valent iron. Iron powder, treated beforehand by a solution of H 2SO 4, was introduced into a glass engine containing a solution of distilled water doped by known quantities of obsolete pesticide and hydrogen peroxide. A continuous mechanical agitation was then applied and samples were taken regularly. The pesticides were extracted by liquid–liquid extraction with hexane and analyzed by a HPLC provided with a UV-visible detector. The results obtained show that the degradation reaction of the DDT is pseudo first-order kinetic which depends on the quantity of iron and pH. The acids, pH largely improve its speed; Fenton oxidation using zero-valent iron as catalytic source of ferro-iron very clearly improves the rate of the DDT degradation; 2,4-DDT is degraded quicker than 4,4-DDT. Fenton oxidation of the DDT provides a promising alternative to the traditional techniques of elimination aslo from the economic point of view.