Polycyclic aromatic hydrocarbons (PAHs) persist in soils due to their low volatility, low water solubility and low biodegradability, all of which make it difficult to remove this type of compound from soils. The work described here involved the study of a combined surfactant-aided soil washing (SASW) process and coagulation treatment, using iron and aluminium salts, to remediate a low-permeability PAH-polluted soil. Phenanthrene was selected as the model PAH and three different types of surfactants (anionic, cationic and non-ionic) were used as washing agents. The results show that the anionic surfactant is the most effective washing fluid because efficiencies higher than 90% can be achieved. Non-ionic and cationic surfactant efficiencies were 70% and 30%, respectively. In addition, only the anionic wastewater can be satisfactorily treated with this technology, with COD removals greater than 90% achieved. Variation of pH, zeta-potential and the dose of aluminium required seem to indicate that a chargeneutralization mechanism is the main process involved in the emulsion break-up obtained in the treatment of aqueous surfactant wastes. In addition, the effects of surfactant concentration and that of the pH of the soil-washing wastewater seem to have a greater influence on the performance of the coagulation process.

A high temperature vapor-fed direct methanol fuel cell (DMFC) has been implemented using H3PO4-doped polybenzimidazole (PBI) as the electrolyte. The influence of the cell temperature, the methanol concentration and the oxygen partial pressure has been studied. This investigation included the evaluation of the cell performance, each electrode potential and crossover current. A lifetime test for 10 days was intermittently carried out in order to assess the stability of the cell response.Increases in the temperature notably enhanced the performance of the cell, although the methanol crossover also increased. The methanol concentration was found to have an optimum value, since a low amount of methanol led to mass transfer limitations and a large amount promoted the crossover and limited the availability of water for methanol oxidation. An increase in the oxygen partial pressure markedly improved the cell response. The higher comburent availability and reduced methanol crossover effect explain this behavior. The study of the combined effect of the oxygen partial pressure and methanol concentration confirmed this effect. The preliminary durability results showed quite stable performance for the cell at a constant current density of 2 100 mA cm -2 . Finally, a comparison between PBI and the traditional DMFC membrane (Nafion  ) was carried out. This comparison showed the PBI-based cell to be a good candidate for DMFC.

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In this work, a pilot plant with two rows of three electrodes in semipermeable electrolyte wells was used to study the electrokinetic treatment of a natural soil polluted with phenanthrene (PHE). The electrokinetic pilot plant was an open system, i.e., there was direct contact between the soil and air. To increase the solubility of phenanthrene, thereby enhancing its transport through the soil, an aqueous solution of the anionic surfactant dodecyl sulfate was used as a flushing fluid. The results show that at the pilot scale considered, gravity and evaporation fluxes are more relevant than electrokinetic fluxes. Contrary to observations at the laboratory scale, desorption of PHE promoted by electric heating appears to be a significant removal mechanism at the pilot scale. In addition, PHE is dragged by the electroosmotic flow in the cathodic wells and by electrophoresis after interaction of the surfactant with phenanthrene in the anodic wells. In spite of the long treatment time (corresponding to an energy consumption over 500kWhm(-3)), the average removal attained was only 25%.

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