CONICET | Buscador de Institutos y Recursos Humanos

Environmental contamination is affecting the three maincomponents of the planet Earth: air, water, and ground.Although all of them are necessary for living organisms,hydric resources are fundamental. As a result of populationgrowth, human and industrial activities have developedwithout the corresponding care of the environment,and hydric resources are being increasingly negativelyaffected [1]. Among the most undesired commonly foundpollutants are toxic metals ions, drug residues, dyes, andagrochemicals [2,3].More than 100,000 types of dyes are constantly beingprepared and employed [4]. They are principally wastedby pulp and paper, plastic, leather, dyeing, pharmaceutical,cosmetic, and textile industries [46]. Their presencein water is sometimes so evident that it can simply beseen by the human eye. In Savar (Bangladesh) a canalshows different colors as red, gray, or blue, depending onthe colors that the nearby factories are using [7]. Thewater in the East River in Xintang (China) has turnedblue as a result of denim industries activities [8], and inthe case of Medrano Creek (Argentina) blue and red colorationshave been observed depending on the samplingtime [9].The presence of dyes in water is especially problematicsince most of these chemical substances are verystable toward solar radiation, humidity, microbial attacks,and oxidizing agents [10,11]. Thus, they are very difficultto be degraded to less harmful products to both humanhealth and the environment. The potential mutagenic andcarcinogenic effects of these kind of chemicals have beenreported [6,1215]. Other negative effects on humanhealth have been reported on the brain, skin, kidney, reproductivesystem, liver, central nervous, reproductive, andendocrine system, among many others [3,5,6,14,16,17].The variety of possible health harmful effects is verybroad, and depends on the type and time exposure.Furthermore, dyes also affect life cycles of species presenton water bodies and, thus, ecosystems that are related tothem, due to the corresponding produced effect on foodchains [10].In order to eliminate the presence of the abovementionedundesired components in both water resources andindustrial wastewater, several methodologies were tested,including physical, chemical, and biological treatments.Coagulation, ion exchange, membrane filtration, reverseosmosis, and adsorption are some of the physical methods[1820]. Among the commonly employed chemicalmethods, oxidation, ozonization, photochemical, and electrochemicalmethods can be mentioned [18,21,22].Aerobic and anaerobic biological treatments and combinedbiological physicalbiological treatments have alsobeen reported [18,23]. Taking account of the cost of processingand instrumentation, and the ease of operation,adsorption processes became very convenient alternativetechnologies for water remediation [24,25].The nature of the materials that are being employedfor dyes removal is very varied, and so too are the experimentalconditions. Among all the possibilities, nanocompositematerials appear as convenient and promisingoptions since they have demonstrated outstanding capabilitiesfor dyes removal. They are composed of at least twomaterials: one composing the matrix while the other oneis acting as the filler or reinforcement at the nanoscale.The final obtained properties are wide and depend notonly on the nature of the components and their specificproportion, but also depend on their methods of preparation.It is very important to remark that it is possible todesign a composite material according to its desiredapplication, with particular emphasis on its efficiency andcapability of reuse.In the present chapter detailed research on nanocompositematerials for different dyes removal and futureperspectives on this topic is presented. Furthermore,exhaustive descriptions and classification of dyes havealso been elaborated.