Fabrication, Characterization And Application Of Polyhydroxybutyrate-Titanium Dioxide Nanocomposite Materials
| dc.contributor.author | Appan, Nanthini Sridewi | |
| dc.date.accessioned | 2020-01-28T07:20:36Z | |
| dc.date.available | 2020-01-28T07:20:36Z | |
| dc.date.issued | 2012-02 | |
| dc.description.abstract | A serious need for a robust, low-cost and eco-friendly method to treat dye pollutants released by textile industries motivated this research. The dye adsorption effect of biodegradable poly-3-hydroxybutyrate [P(3HB)] and the photocatalytic degradation ability of inert titanium dioxide (TiO2) was exploited to fabricate a multifunctional nanocomposite film via solvent casting and electrospinning. The environmental degradation of the choice material, cast P(3HB) was first tested and confirmed to be comparable to its co-polymers; poly(3-hydroxybutyrate-co-5 mol% 3-hydroxyvalerate) [P(3HB-co-5 mol% 3HV)] and poly(3-hydroxybutyrate-co-5 mol% 3-hydroxyhexanoate) [P(3HB-co-5 mol% 3HHx)]. The weight loss was almost complete by 8 weeks in tropical mangrove sediment. The nanocomposite film was also degradable although to a lesser extent despite the microbial inactivation effect of TiO2. The optimum amount of P(3HB) and TiO2 loading in cast film was found to be 0.4 g and 40 wt% respectively. This film had an even distribution of TiO2 when mixed concurrently in chloroform followed by stirring for 24 h. It completely decolorized and detoxified real industrial Batik dye wastewater in 3 h and induced a chemical oxygen demand (COD) reduction of 80%. The 0.4 g P(3HB)-40 wt% TiO2 film exhibited good stability with decolorization percentage of ≥80% even after the sixth repeated usage. The decolorized Batik dye wastewater had no toxic effects on mosquito larvae, Aedes aegypti and microalgae, Scenedesmus quadricauda. Novel P(3HB)-TiO2 ultrathin fibers electrospun from CHCl3/DMF (8:2) mixed solvent showed enhanced photocatalytic activity. The maximum TiO2 loading in 4 w/v% P(3HB) was 50 wt%. Applied voltage and extrusion rate of 15 kV and 40 μL min-1 respectively produced homogeneous P(3HB)-50 wt% TiO2 fibers with mean diameter of 780 nm. Interestingly, in the absence of irradiation, electrospun (3HB) film exhibited superior ability in decolorizing (78%) 30 μM Malachite Green (MG) via adsorption alone whereas the corresponding value of cast P(3HB) was only 24%. The electrospun P(3HB)-50 wt% TiO2 completely decolorized MG in 45 min under solar irradiation, which corresponded to 58.7% COD removal. MG solution treated this way was non-toxic against A. aegypti larvae. This film retained higher photocatalytic stability than its cast counterpart. It was re-applicable for at least 10 times with ≥98% decolorization efficiency. It also showed efficient bactericidal effect against Escherichia coli under UVA illumination with 1-2 orders of magnitude more than the cast P(3HB)-50 wt% TiO2. An effective, inexpensive, safe and reusable method for decolorization, mineralization, detoxification and disinfection of textile dye wastewaters was successfully developed in this research. | en_US |
| dc.identifier.uri | http://hdl.handle.net/123456789/9467 | |
| dc.language.iso | en | en_US |
| dc.subject | Factory and trade waste | en_US |
| dc.title | Fabrication, Characterization And Application Of Polyhydroxybutyrate-Titanium Dioxide Nanocomposite Materials | en_US |
| dc.type | Thesis | en_US |
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