engleski

Presence of CdSe/ZnS Core Shells Quantum Dots in Water Matrix: Pollutants or Catalysts for Water Treatment

In the last decade nanotechnology became one of the fast-growing fields producing variety of commercial nanoparticles. These materials are characterized with significantly different properties in comparison to either components in their pure form, or with composites in which both of the phases have macroscopic dimensions. Quantum dots, made from semiconductor nanostructure that confines the motion of conduction band electrons, valence band holes, or excitons in all three spatial directions, represent one of such newly designed materials. Due to their superior transport and optical properties, quantum dots are being applied in diode lasers, amplifiers and biological sensors. In the recent years, correspondingly with their increased production and application, the number of scientific papers mostly studying the development and new design for their synthesis and production, as well as their application in medicine, optics and electronics, increased. Considering the increased need for them, it could be expected that their presence in the environment would significantly increase in the near future due to their release either during production process or following their applications. Since quantum dots, like a lot of other nanoparticles are still not yet well-characterized or understood, the potential risks and damages to the environment are still unknown and should be investigated. This study was focused on the investigation of behavior, the possible reactivity of quantum dots nanoparticles, CdSe/ZnS core shells, in water matrix, and their interactions with standard organic pollutants during the simulated water/wastewater treatment processes. The patterns of changes in mechanisms of degradation of selected organic compounds in the presence of quantum dots (CdSe/ZnS core shells) under controlled conditions were studied. In that purpose standard chemical oxidative processes, such as UV radiation, as well as the UV-based advanced oxidation process UV/H2O2 were applied for the treatment of model wastestream containing organic load and CdSe/ZnS core shells. Since CdSe/ZnS core shells (QD) are made from semiconductor material, it was expected their behavior as a typical photocatalyst. Our preliminary results have shown the inhibitory effect of QDs in the first stage of treatments, and the catalytic effect with the prolonged exposure time. Also, results suggest that the presence of CdSe/ZnS core shells leads to different degradation pathways of studied organics.

nanoparticles; CdSe/ZnS core shells; wastewater treatment; organic pollution; UV irradiation

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