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Title:	The influence of adding iron oxide nanoparticles in biohydrogen production through mixed culture fermentation in thermophilic condition
Authors:	Nurul Sakinah Engliman (P80201)
Supervisor:	Jamaliah Md Jahim, Prof. Dr.
Keywords:	Hydrogen -- Biotechnology Nanostructured materials Universiti Kebangsaan Malaysia -- Dissertations Dissertations, Academic -- Malaysia
Issue Date:	19-Jul-2018
Description:	Recently, global attention focused on hydrogen gas as one of the most promising, eco-friendly and renewable energy sources. Nowadays, biological process has been chosen to produce hydrogen extensively, especially anaerobic fermentation due to its ability to utilize various type of biomass, simple and cheaper technology. However, the challenge in using anaerobic fermentation to produce biohydrogen was due to low energy conversion and process selectivity. Biohydrogen production can be enhanced by addition of micronutrients such as metal ions to improve the metabolic reaction of the bacteria involved in the process. Metal ion in nano-sized is effective as it provide higher surface area for reaction site but, the application of nano-sized micronutrient not yet been done in thermophilic condition. Furthermore, there is limited information on the effect of adding nano-sized metal ion on the bacterial growth and its kinetic. Thus, this study aimed to investigate the effect of adding iron oxide NPs in biohydrogen production in term of bacterial growth, its kinetic effect as well as its mechanism that been conducted either in suspended or in immobilized way. Iron oxide NPs was fabricated using forced hydrolysis method with the average size 50±4nm. In the suspended system, addition of iron oxide NPs able to enhance the H2 production up to 32% with a yield 1.92 mol H2/mol glucose as compare to the control experiment without any addition of nanoparticle. Later, the iron oxide NPs was immobilized on the PVDF membrane through polymerization method. The fermentability test showed that when iron oxide NPs was immobilized on the surface of the membrane, the productivity was improved about 27% from suspended system with the yield increased to 2.43 mol H2/mol glucose. Kinetic study showed that the bacterial growth started to reduce when iron oxide NPs was more than 200 mg/l as excessed iron oxide NPs become inhibitor to the system as it slowing down the bacterial grow and thus, affect the biohydrogen production. The interaction study betbetween bacteria and iron oxide NPs was done by physical and chemical analysis through microscopic and oxidation-reduction potential (ORP) analysis. Atomic force microscope (AFM) and transmission electron microscope (TEM) results showed that iron oxide NPs act as a bridge between one bacterial cells to another and thus, formed bacterial sedimentation. Sedimentation of cells enhanced the metabolic activity of the bacteria and this has been proven by the oxidation-reduction potential (ORP) analysis where the ORP increase when bacterial sediment was presence and decreased gradually when the sample become homogenous. The performance of adding iron oxide NPs for biohydrogen production was further investigated under semi-continuous system inside a small anaerobic reactor. The results showed that the system with immobilized iron oxide NPs produced more biohydrogen with the yield of 2.64 mol H2/mol glucose, which is 31% higher than when iron oxide NPs was in suspended formed during the fermentation. It was found that the fermentation performance was improved for both suspended and attached iron oxide NPs when the hydraulic retention time (HRT) was shorten to 12 hours to achieve maximum hydrogen production rate. The bacterial analysis done from 16s RNA determination showed that the dominant bacteria was Thermoanaerobacterium sp. in all operated HRTs for both suspended and immobilized system involved in this fermentation. Thus, this research proved that adding the iron oxide NPs is important as it is able to contribute in enhancing biohydrogen production by shorten the production time and improve the bacterial activities. - ,Ph.D.
Pages:	215
Call Number:	TP248.65.H9N8485 2018 3 tesis
Publisher:	UKM, Bangi
Appears in Collections:	Faculty of Engineering and Built Environment / Fakulti Kejuruteraan dan Alam Bina

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