DDT REMOVAL BY NANO ZERO VALENT IRON: INFLUENCE OF pH ON REMOVAL MECHANISM

Abstract

Persistent organic compounds are resistant tobiological degradation and can be transported long distances by releasing intothe atmosphere and can be found in the atmosphere for a long time. DDT is oneof the persistent organic compounds which is prohibited by StockholmConvention. Against the prohibition in many countries, DDT, which is still inlimited use in undeveloped countries, has a very low carcinogenic concentration(0,23 μg/L). It is stated in the literature that nanomaterials have been usedeffectively in the last decades for the removal of environmental pollutants. Inthis study, the mechanism of removal by nano zero valent iron was investigatedby researching the pH effect at low DDT concentration. pH and ORP changes aftertreatment were investigated. Almost total DDT was removed within 5 minutes andpH effect on removal mechanism has found to be negligible. The ORP valuesdecreased rapidly during the first minutes of the study. In addition, theeffluent Fe2+ concentrations were also investigated and theseresults showed that oxidation was effective in the removal mechanism.