| Summary: | 碩士 === 國立臺灣大學 === 環境工程學研究所 === 107 === The use of graphene sponge in treating wastewater has been studied for some years. Relevant results have suggested the active role of graphene oxide sponge in oils and organic dyes removals. Despite its effectiveness, its use in the market is rarely observed due to its high cost in manufacturing. To reduce the cost, instead of coating graphene on the surface of sponges, this study selected a synthesizing process of graphene sponge which combined both polyurethane and graphene simultaneously. This research investigated the various contaminant removal capabilities of graphene sponge by using a low-cost production method.
This article engaged three different pollutants, namely, oils, Methylene blue (MB) solution, and volatile organic compounds (VOC). The gravimetric method was adopted to achieve the adsorption kinetics of different oil solutions. The graphene sponge was weighted every 10 seconds to obtain the sponge adsorption rate and maximum capacity. An air compressor was used to desorb the oils from the graphene sponges for reusability test. The removal of Methylene blue solution was investigated by utilized a spectrophotometer to analyze the concentration of MB. The initial and final concentrations of Methylene blue solution were measured to calculate the Methylene blue adsorption capacity of the graphene sponge. The removal of propane and butane were studied by the use of graphene sponge as an air filter. The Gas Chromatography (GC) was applied to quantify the concentration of both volatile organic compounds.
The success of the coating method in this research is strongly suggested by the different surface appearances of regular sponge and graphene sponge demonstrated in the Scanning Electron Microscope (SEM). This conclusion is further supported by the analysis of X-ray Photoelectron Spectroscopy (XPS). The capacity experiment results show that the graphene sponge is more effective in adsorbing high viscosity oils compared with low viscosity oils (12.4g/g and 11.6 g/g respectively). As for the Methylene blue solution, high pH value of Methylene blue solution is superior to low pH value in the removal capacity (93% and 22% respectively). In the case of VOCs, graphene sponge has no significant ability to remove the gaseous contaminants.
Though the smaller amount of graphene inside the synthesis graphene sponge in this research led to the relatively low adsorption performance compared to those of the other previous research which possessed a higher percentage of graphene, this could be solved by increasing the percentage of graphene content during the combining process. This research may provide an alternative manufacturing process of graphene sponges in the future, as the synthesizing method, which is now able to be produced in factories, is comparably cheap and practically achievable.
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