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Enhancement of Semiconductor Mediated Photocatalytic Removal of Polyethylene Plastic Wastes from the Environment by Oxidizers

Author Affiliations

  • 1School of Environmental studies, Cochin University of Science and Technology, Kochi 682022, INDIA

Res. J. Recent Sci., Volume 4, Issue (10), Pages 105-112, October,2 (2015)


Plastics have become an essential ingredient of modern life with wide range of applications. At the same time the ‘white pollution’ caused by plastic wastes is a major environmental problem due to their recalcitrant nature. Even the simplest form of plastics, i.e., polyethylene is strong and highly durable and takes upto 1000 years for natural degradation in the environment. Current study reveals that photocatalysis can be used successfully as an Advanced Oxidation Technique for the slow but steady degradation of polyethylene plastics (PEP). Semiconductors such as ZnO and TiO assist the photodegradation of PEP through the generation of highly reactive free radicals which interact with the pollutant. TiO is at least 20% more efficient than ZnO as a photocatalyst in this respect. The process is pH dependent and acidic condition favours the degradation. Oxidizing agents such as H2 and peroxydisulphate (PDS) accelerate the semiconductor catalysed degradation. The enhancement depends on the concentration of the oxidizer and stabilises at an optimum range. Critical parameters for optimum efficiency for the degradation of PEP are identified and evaluated. A tentative mechanism for the degradation is also proposed based on the observations.


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