Organic compounds have been identified as major challenges in not only waste water management but also for large scale catastrophes such as the Elk River incident occurred in 2014, where thousands of gallons of 4-methylchlorohexane and methanol was discharged into a tributary of the Ohio River and for large slick of pollutants such as oil spills. In all these cases, conventional water treatment methods are not strong enough to degrade the organic compounds. Advanced oxidation processes, including photocatalytic degradation have been developed as a remedy. Transition metal oxides as photocatalysts have attracted a lot of attention because of their stability, non-toxicity and low cost. However, when metal oxides are used in any powder form, they form stable suspensions in the water, which are difficult to remove from the treated water. Additionally, some metal oxides such as TiO2 have wide band gaps implying that only UV (only 5% of the whole solar spectrum) can enhance their photocatalytic reactions. As an alternative, WO3 has a band gap of 2.6eV implying that its photocatalytic reactions can be enhanced by visible light (45% of the solar spectrum). Additionally, incorporation of the WO3 powder into a buoyant material such as poly dimethyl siloxane (PDMS) makes it float on water and thus formation of suspensions is eliminated. In cases of oil spills and discharge of large number of organic compounds into a water source, a buoyant photocatalyst that can utilize visible light for its photocatalytic reactions is really needed. In this research, tungsten (VI) Oxide was incorporated into PDMS beads and used to degrade methylene blue (MB) under UV-radiations. MB lost color entirely by the end of the degradation process and the photocatalyst was successfully filtered off the clear water using a filter paper. Characterization of WO3/PDMS was done by SEM, EDS, BET and Raman spectroscopy, both before and after using them for degradation. In all cases, the crystal structure of WO3, element composition and surface morphology remained unaltered. This confirms that incorporation of WO3 in to PDMS beads makes it buoyant without altering it nature and thus easy to separate from water after the whole treatment process.

Incorporation of metal oxides into a polymer substrate for buoyant photocatalysts

2019 Spring National Meeting

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