A INFLUÊNCIA DAS CARACTERÍSTICAS DOS SOLOS NA REMEDIAÇÃO DE LOCAIS CONTAMINADOS ATRAVÉS DE PROCESSOS OXIDATIVOS AVANÇADOS COM PERSULFATO E REAGENTE DE FENTON THE INFLUENCE OF SOIL CHARACTERISTICS IN REMEDIATIO N OF CONTAMINATED SOILS THROUGH ADVANCED OXIDATION PROCE SS WITH SODIUM PERSULFATE AND FENTON REAGENT

The remediation techniques used in contaminated soils such as "in situ" chemical oxidation aim essenti ally the mineralization of contaminants, reducing it to CO2 and H2O. The objective of this study is pointing ou t the results of experi- ments conducted to investigate how the soil charact eristics such as granulometry, assay and nature of clay minerals as well as organic matter can influence in the mineralization performance of linear alkylbenzene in the soil. In some areas of Sao Paulo city there are contaminated sites by leakage of lin ear alkylbenzene and many other chemical leakages and site's responsible and local authorities are interested in possible te chnical solutions to clean it. One possible solutio n would be in situ treatment through advanced oxidation process; however there i s no way how to decide about the best technique bec ause it depends on contaminant substance, reagents used as well as the contaminated soil characteristics. The answer coul d be scientifically based on bench laboratory experiments properly designed t o investigate the factors that control the process performance. The bench lab experiments were conducted with two soils sampled from metropolitan region of Sao Paulo and contaminated with linear alkyl benzene, used in high and medium voltage underground electrical cables. The mineralization perfo rmance was evaluated in soils contaminated with an initial concentration of 10 mg / gr of contaminated soil by oxidation of linear alkyl benzene with Fenton reagent and sodium persulfate. The final res ults pointed out a considerable mass reduction from 82% to 85% in both soils tested with sodium persulfate thermally activ ated and by naturally available transition metal Fe 2+ in the soil. The Fenton reagent in the same experiment conditions pointed o ut a more limited mass reduction performance between 10% and 30%. The previous knowledge of soil characteristics such as particle size ,clay assay , natural carbon cont ent in the soil which influ- ence the sorption / desorption phenomenon as well a s the mineral composition of the soil are the key v ariables to define rea- gents and the oxidation reaction conditions which c ontribute to select a proper in situ chemical oxida tion technology