| Popis: |
TCE (Trichloroethylene) is a chlorinated solvent, known for its toxicity present in many underground water reservoirs and, as it is a less viscous and denser contaminant than water, it reaches the impermeable substrate of the reservoirs, remaining trapped in the water system pores for years or decades. The TCE removal technique studied in this work is the reduction by nanoparticles of zero valent iron. In this case, Fe0 acts as an electron donor so that TCE is reduced to less harmful compounds that are easier to remove. And, just as important as the reduction of TCE through the chemical reaction, are the pressure disturbances caused by the injection of the solution of nanoparticles and by the gas that is one of the products of the reaction. These disorders can displace the TCE from the interior of the pores, facilitating its later removal. Through computational fluid dynamics simulations, using openFOAM free software, it was possible to prove that ethylene, which is one of the products of the TCE reduction reaction, is capable of displacing DNAPL from the interior of the pores. Through two-dimensional simulations, a 97% reduction in TCE saturation was obtained due to displacement of the contaminant out of the field of view. It is also worth noting that the simulations performed were consistent with experimental results performed by other authors. In addition, the behaviour of the TCE - water flow was also evaluated as a function of the contact angle TCE - water - grain wall. In this case, there was a greater recovery of the TCE for its drainage condition, with contact angles of approximately 140º. |
