利用硫醇分子合成金奈米團簇應用於檢測自來水及游泳池水中次氯酸根
隨著大眾對於衛生要求的上升,許多抗菌及消毒成分被廣泛應用於水質處理中,其中次氯酸作為消毒殺菌劑大量使用於泳池及自來水的水質淨化中,然而現行標準方法測定水中有效氯所使用具危害的毒化物且步驟繁雜不利普及民生使用,發展簡便快速且靈敏的偵測方法勢在必行。本研究利用牛血清白蛋白(Bovine serum albumin, BSA)、不同的硫醇分子及金離子合成具螢光特性之硫醇修飾金奈米團簇 (Thiol ligand assists BSA capped gold nanoclusters, BSA/RSH-Au NCs),探討添加不同硫醇分子對所合成之金奈米團簇於不同pH值及常見離子對螢光強度之影響,並利用具有最佳螢光穩定性之2-巰基苯甲酸修飾金奈米團簇(Thiosalicylic acid assists BSA capped gold nanoclusters, BSA/TA-Au NCs),透析後進行次氯酸根檢測,其檢測線性範圍為0.98μM-1000μM,涵蓋法規規定游泳池水及自來水中次氯酸根之容許殘留濃度,最後此方法成功於游泳池水及自來水基質中檢測次氯酸根,分析樣品的回收率介於94.4%-95.6%。此外,在紙上添加金奈米團簇,並加入不同濃度的次氯酸根,觀察其螢光強度的變化,期望此方法未來應用於快篩試紙塗布材料快速檢測水質中次氯酸根濃度。
Synthesis of Mesoporous Carbons and Their Application for EDLC
The quick increasing energy consumption arouses the interest in the development of power storages. Electrochemical supercapacitor is one of clean and sustainable candidates of energy storage system, and porous carbons are the most potential candidate as electrode materials for electrochemical supercapacitor because of their large surface areas, high chemical and physical stability, good conductivity, as well as low cost. In this work, we synthesized the mesoporous carbons by using ZnO nanoparticles as sacrificing template via nano-casting synthetic process and natural porous carbon materials. The synthesized porous carbon has a mesoporous structure. Because the surface area and pore size of the synthesized mesoporous carbon are larger than that of the coconuts fiber-derived carbon, the CV plots show that the synthesized mesoporous carbon has a good rectangular shape and a much better performance than that of the coconuts fiber-derived carbon. We also develop an easy way to discriminate how well a supercapacitor works. We applied these porous carbon-based electrodes on both handmade as well as the commercial capacitors and measured their electrical performances. The handmade EDLC is less efficient than the commercial capacitor.
Chlorella vulgaris chlorophyll a fluorescence as a potential indicator for zinc and nickel detection
Heavy metals contaminate many bodies of water, posing a health risk to not only organisms that live and use the water in these areas, but also to the humans that live nearby. Chlorella vulgaris, a microalga, is one organism whose chlorophyll a fluorescence can indicate the presence of these substances, detecting any changes in concentrations using fluorescence microscopy and other fluorescence devices. The study explores the sensitivity of C. vulgaris to the heavy metal zinc where the algae was exposed to five concentrations of zinc: 0 ppm, 5 ppm, 10 ppm, 50 ppm, and 100 ppm. The fluorescence of the samples was observed with a fluorescence microscope on days 0, 4, 7, and 12, where the algal samples were adapted to the dark for 5 minutes, then exposed to light for 90 seconds. The values of the minimal and maximal fluorescence of the samples in the dark were noted. There is a significant difference in the values of the minimal fluorescence, maximal fluorescence, and maximum quantum yield, a value derived from the minimal and maximal fluorescence, at the highest concentration, 100 ppm, from the other treatments for the entirety of the experiment. The significantly low values at 100 ppm and the calculated EC50 of 75.70 ppm indicate that C. vulgaris is indeed a viable indicator for zinc detection at this and higher concentrations of zinc.
Synthesis of Biodegradable Plastic From Food Waste
Based on NEA Waste Statistics and Overall Recycling Rate for 2017, 809,800 tonnes of food waste and 815,200 tonnes of plastic waste was generated. Both food waste and plastic waste account for more than 10% of the total waste generated in Singapore in 2017 respectively. However only 16% of the food waste and 6% of plastic waste was recycled, the rest of it was disposed at the incineration plants and then the landfill. Such action will eventually lead to 2 major environmental issues that Singapore will face in near future: 1)Semakau landfill is our only landfill left and it is expected to run out of space in near future 2)The burning of food waste results in the release of methane (CH4), a greenhouse gas that has over 25 times the impact in trapping excess heat in the atmosphere as compared to Carbon Dioxide (CO2). This will increase carbon footprint and contribute to greenhouse effect and global warming in due course. According to the Sustainable Singapore Blueprint 2015, Singapore is working towards becoming a Zero Waste Nation by reducing our consumption, reusing and recycling all materials. A national recycling rate target of 70% has been set for 2030 with an aim to increase domestic recycling rate from 20% in 2013 to 30% by 2030 and non-domestic recycling rate from 77% in 2013 to 81% by 2030. As part of our total commitment towards waste management and sustainability effort, the purpose of doing this research project is to investigate whether food waste can be recycled and made into biodegradable plastics. First of all, chitosan will be derived from shrimp shells and be dissolved in acetic acid and lactic acid produced by probiotic fermentation of fruit and/ or vegetable waste for synthesis of biodegradable plastics.