Abstract
 The multiple forms of structuring transition metal anions in solution are important aspects to be taken into account obtaining oxides these metals by the sol-gel method. formation polyanions aqueous media can produce a variety structures solid state. Films were obtained through method with sodium tungstate as precursor and dodecyltrimethylammonium chloride (DTAC) agent, after cal...

After treated, sewage can be reused for different purposes such as production processes, cleaning, irrigation and others. Depending on the type of treatment they result in an effluent with a high pH (> 10.0), which is necessary to decrease because it exceeds the maximum permissible average limit (LMPP) of the Cuban standards of wastewater discharge to the coastal and marine waters (NC 521:2007)...