Condutividade eletrosmótica e remediação de solos contaminados com cádmio via eletrosmose

• Autor(a) principal: Velten, Rodrigo Zorzal
• Data de Publicação: 2008
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/3696
• topic: Fenômenos eletrocinéticos; Eletrosmose; Remediação de solo contaminado com cádmio; Condutividade eletrosmótica; Latossolo Vermelho-Amarelo; Electrokinetic phenomena; Electroosmosis; Cadmium- contaminated soil remediation; Electroosmotic conductivity; Red Yellow Latosol; CNPQ::ENGENHARIAS::ENGENHARIA CIVIL::GEOTECNICA

This research addressed the application of electrokinetic phenomena in soil remediation, considering the application of electroosmosis in the decontamination of three soils from the Zona da Mata Norte, Minas Gerais state, Brazil, contaminated with the element-trace cadmium. This work followed a line of research previously developed at the Universidade Federal de Viçosa, including the evaluation of the electroosmotic process in the chemical and mineralogical parameters of a larger gamma of soils, as well as evaluating the effect of testing parameters in the efficiency of the decontamination process. The tested soils were residual products from gneiss, as follow: (i) soil 1, a mature residual soil, pedologically classified as Red Yellow Latosol, presenting lateritic geotechnical behavior and silty-sandy-clayey texture; (ii) soil 2, saprolitic, presenting non lateritic geotechnical behavior and clayey-silty-sandy texture; e (iii) soil 3, also a mature residual soil, pedologically classified as Red yellow Podzol (Argisol), presenting non- lateritic geotechnical behavior and sandy-siltyclayey texture. Cadmium was the element- trace used in the experiment because it is a usual polluting source in daily use objects and presents adsorption-desorption intermediate behavior. The study program was directed to the analysis of soil behavior before and after their contamination with cadmium, encompassing the following steps: (i) X-rays analysis; (ii) physical and chemical routine tests; (iii) determination of CEC and ZPC; (iv) evaluation of the influence of the applied compaction effort and, therefore, of structure, in the soils eletrosmotic conductivity coefficient; (v) evaluation of the influence of the applied electrical potential difference (ddp) of 5, 15 and 30 V in the electrokinetic decontamination process; (vi) analysis of the influence of the contaminant incubation time (periods of 1, 10 and 20 days) and of ddp (5, 15 and 30 V) in the decontamination process. The results had shown that: (i) quartz predominated in the soils sand fraction, whereas kaolinite predominated in the soils silt and clay fractions; however, it was observed significant presence of hematite and gibbsite in the clay fraction of soil 1 and of goethite in the clay fraction of soil 3; (ii) electrochemically, soils 1 and 3 revealed more active behavior, presenting higher specific cation adsorption capacity; (iii) the parameter ZPC was a determinant factor in all the analyzed soils chemical properties, as well as in the electrokinetic decontamination process, governing the direction of the eletrosmotic flow and influencing in the results of the decontamination applied technique; (iv) the addition of the contaminant to soils was responsible for significant changes in the routine analysis and in the CEC and ZPC parameters, specially regarding soils 1 and 3, which are the most active ones; (v) except for soil 3, the values of the electroosmotic conductivity coefficient of soil was not significantly influenced by the application of different electric potentials and different compaction efforts; (vi) for all tested soils, cadmium soils removal through electrokinetic phenomena increased significantly with the increase of the incubation time and with the increase of the applied electric potential difference.