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Alexandre y Dubois, 2000 Nanocomposites are a new class of composites, that are particle-filled polymers for which at least one dimension of the dispersed particles is in the nanometer range. One can distinguish three types of nanocomposites, depending on how many dimensions of the dispersed particles are in the nanometer range. When the three dimensions are in the order of nanometers, we are dealing with isodimensional nanoparticles, such as spherical silica nanoparticles obtained by in situ sol±gel methods [1,2] or by polymerization promoted directly from their surface , but also can include semiconductor nanoclusters  and others . When two dimensions are in the nanometer scale and the third is larger, forming an elongated structure, we speak about nanotubes or whiskers as, for example, carbon nanotubes  or cellulose whiskers [6,7] which are extensively studied as reinforcing nanofillers yielding
Virus= Andrei Riciu Bacteria=Discover magazine Membrana celular= Nicholson S. 2010
Gullupalli y Barron, 2000
En México superficie afectada D. Química: 320 mil km2 D. Física: 85.14 Erosión hidrica: 235.95 km2 Erosión eólica: 293.64 Fuente: SEMARNAT, 2006
SISCO, SEMARNAT, 2012
Citrate-Coated Gold NPs As Smart Scavengers for Mercury(II) Removal from Polluted Waters. The available supplies of freshwater are decreasing due to extended droughts, population growth, and increasing groundwater and environmental pollution . ... (1) Natural sources of contamination by mercury are volcanic eruptions and mercury-rich soils , containing an average of 80 ppb of Hg, whose eluviations contribute to its accumulation in water streams. Remosión con magnetita Fe 3 O 4. Sanchez 2011.
Cundy et al., 2008
the increasing use of zinc oxide nanoparticles (ZnO NPs) in consumer and industrial products highlights a need to understand their potential environmental impacts. In this study, the response of anaerobic granular sludge (AGS) to a shock load of ZnO NPs during anaerobic biological wastewater treatment was reported. It was observed that the extracellular polymeric substances (EPS) of AGS and the methane production were not significantly influenced at ZnO NPs of 10 and 50 mg per gram of total suspended solids (mg/g-TSS), but they were decreased when the dosage of ZnO NPs was greater than 100 mg/g-TSS. The visualization of EPS structure with multiple fluorescence labeling and confocal laser scanning microscope revealed that ZnO NPs mainly caused the decrease of proteins by 69.6%. The Fourier transform infrared spectroscopy analysis further indicated that the C–O–C group of polysaccharides and carboxyl group of proteins in EPS were also changed in the presence of ZnO NPs. The decline of EPS induced by ZnO NPs resulted in their deteriorating protective role on the inner microorganisms of AGS, which was in correspondence with the observed lower general physiological activity of AGS and the death of microorganisms. Further investigation showed that the negative influence of ZnO NPs on methane production was due to their severe inhibition on the methanization step. Lindano= 1,2,3,4,5,6-hexaclorociclohexano
Removal and recovery of Mo(VI) from aqueous solutions were investigated using maghemite (γ-Fe 2 O 3 ) nanoparticles. Combination of nanoparticle adsorption and magnetic separation was used to the removal and recovery of Mo(VI) from water and wastewater solutions. The nanoscale maghemite with mean diameter of 50 nm was synthesized by reduction coprecipitation method followed by aeration oxidation. Various factors influencing the adsorption of Mo(VI), e.g. pH, temperature, initial concentration, and coexisting common ions were studied. Adsorption reached equilibrium within <10 min and was independent of initial concentration of Mo(VI). Studies were performed at different pH values to find out the pH at which maximum adsorption occurred. The maximum adsorption occurred at pHs between 4.0 and 6.0. The Langmuir adsorption capacity ( q max ) was found to be 33.4 mg Mo(VI)/g of the adsorbent. The results showed that nanoparticle (γ-Fe 2 O 3 ) is suitable for the removal of Mo(VI), as molybdate, from water and wastewater samples. The adsorbed Mo(VI) was then desorbed and determined spectrophotometrically using bromopyrogallol red as a complexation reagent. This allows the determination of Mo(VI) in the range 1.0–86.0 ng mL −1 . Abbas Afkhami , , Rasoul Norooz-Asl