International Science Community Association Research Journal of Recent Sciences 2277 - 2502 1 10 2012 October 2 Waste Water Treatment by Precipitating Copper, Lead and Nickel Species 1 6 EN Espinoza E. 1 Instituto de Investigaciones Metalurgicas, Universidad Michoacana de San Nicolas de Hidalgo, Ciudad Universitaria Edificio ”U”, Apartado Escudero R. 2 postal 888, C.P. 58000, Morelia, Michoacán, MÉXICO Tavera F.J. 3 > Research Paper 2012 3 17 2012 October 2 Precipitation of metallic species in either, liquid-liquid, solid-solid, or liquid-solid systems is a current phenomenon that is related with the formation and/or deposition of second phases. An example of the above is the deposition of some precipitated species on ore particles during milling, changing their surface properties and affecting the process of capture during flotation. Precipitation of species also occurs during waste water treatment. Despite the fact that several procedures have been designed to clean water contaminated with heavy metals (i.e., activated zeolite and membranes, gas dispersion devices, bird feathers, biological procedures, etc.) the mechanisms describing the formation of such phases or species are not well understood. This work establishes from a thermodynamic point of view the conditions (pH, electrochemical potential, ionic strength, activity coefficient) to predict the formation of certain species (precipitated or dissolved) in distilled water contaminated with lead, copper, and nickel, and open to the atmosphere. The pH of the media was varied from 3 to 13. Experimental results show the feasibility to control selectively the precipitation of given copper, nickel, and lead species from contaminated water, by controlling the pH of the liquid media. From the information derived in this work, it is possible to design a process for cleaning water contaminated with heavy metals by promoting the sedimentation of metallic species, and to predict or avoid the formation of certain species on ore particles that reduce the metallurgical efficiency during the flotation process. Copyright@ International Science Community Association