AN EFFECT OF PHOSPHORYLATION CONDITIONS ON THE CHARACTERISTICS OF PHOSPHORYLATED CHITOSAN MEMBRANE AS AN ELECTROLYTE FOR FUEL CELL
Recently, fuel cells have been developed as an alternative energy to substitute fossil fuels. One type of fuel cells that attracts much attention is Direct Methanol Fuel Cell <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <...
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| Format: | Theses |
| Language: | Indonesia |
| Online Access: | https://digilib.itb.ac.id/gdl/view/15630 |
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| Institution: | Institut Teknologi Bandung |
| Language: | Indonesia |
| Summary: | Recently, fuel cells have been developed as an alternative energy to substitute fossil fuels. One type of fuel cells that attracts much attention is Direct Methanol Fuel Cell <br />
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(DMFC). A DMFC uses methanol as a fuel and proton exchange membrane as an electrolyte. Nafion is a commercial proton exchange membrane that is most commonly used in DMFC. However, Nafion is expensive and has a high methanol <br />
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permeability that can limit the large-scale commercialization of DMFC. Therefore, efforts have to be done to find other polymers to substitute Nafion. Chitosan is one of the polymers that can be used for this purpose as it has been widely studied due to its potential benefits. Unfortunately, the proton conductivity of chitosan is still lower than Nafion. Based on the previous research, it was found that microwave-assisted phosphorylation of chitosan membrane using orthophosphoric acid, urea, and N,Ndimethylformamide (DMF) has enhanced its proton conductivity. In this research, further studies about phosphorylation was conducted to obtain the optimal condition of phosphorylation. Phosphorylation was carried out by continuous or discontinuous reaction for 60 seconds and by immersion of chitosan membrane on orthophosphoric <br />
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acid prior to phosphorylation reaction. The continuous reaction indicated that the microwave-assisted phosphorylation was carrried out during 60 seconds, while the discontinuous one indicated that the reaction was done in six sequences of ten seconds each. Chitosan membranes were immmersed in various time ranging from one to six hours. Several characterizations of the resulting membranes were carried out such as functional groups analysis by FTIR, swelling index, ion-exchange capacity (IEC), proton conductivity, surface analysis by Scanning Electron <br />
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Microscope (SEM), phosphorus content on surface membranes by Energy Dispersive X-Ray Spectroscopy (EDS), and methanol permeability. It was found that phosphorylation by continuous reaction and 4 h-immersion resulted in membrane <br />
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with optimum proton conductivity and IEC which are 0.0789 S/cm and 11.21 meq/g, respectively. Membranes prepared by the same reaction condition also showed high swelling index (40.83%). Compared to membranes without any immersion in the reaction mixture, the immersed membranes showed higher phosphorus content. It can be concluded that the continuous and 4h-immersion was found as the optimum phosphorylation conditions for preparing the chitosan-based polymer electrolyte membrane. |
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