微囊藻毒(Microcystins)是由藍綠藻因藻華現象而衍生出來的一種代謝物，其中微囊藻毒LR型(Microcystin-LR)為毒性最強的代謝物。為了加快反應時間及減少氧化劑的使用量，吾人於研究中加入了自行研發之鎳矽氧化物(NiSiOx)觸媒來處理含有微囊藻毒之模擬水溶液。本研究使用了SEM、SEM-EDS及XRF來檢測驗觸媒成分；而為了找出能夠被觸媒催化的氧化劑，本研究也有嘗試了不同的氧化劑配合觸媒來做測試。測試結果發現鎳矽氧化物觸媒能夠有效的催化次氯酸及過一硫酸鉀。由比於經觸媒催化的次氯酸具有更優秀的降解微囊藻毒能力，故本研究所選用的氧化劑為次氯酸。
　　本研究的實驗變因為氧化劑濃度、初始酸鹼值以及外加腐植酸來探討系統的影響。實驗結果顯示，在反應時間為30分鐘的條件下，反應pH值為3及7的條件能達到90%以上的微囊藻毒去除率，最佳的操作條件為在固定1g/L的鎳矽氧化物觸媒、微囊藻毒濃度為0.1μM pHr = 7以及[HOCl] = 20μM，微囊藻毒的降解率為94.7%，在實驗結束後也有使用相關儀器分析水溶液中的重金屬殘餘量。而本研究也有針對降解微囊藻毒以後所產生的中間產物進行相關研究，並推導出可能的降解反應機制。實驗給果證實在加入觸媒後，皆能提高次氯酸氧化微囊藻毒的降解率及加快了反應時間。

Microcystin-LR (MC-LR) is the most toxic pollutant produced from cyanobacteria. It found that it was deathful when mammal intake small amount of MC-LR. To remove the MC-LR, some of the literature has been published since 1990s. To increase the performance of degradation of MC-LR and decrease the reaction time, this work used oxidant with catalyst NiSiOx, which the catalyst made by UNIST Prof. Lee’s Lab, to remove the MC-LR. Effectiveness of MC-LR degradation was then evaluated by varying the pHr, concentration of oxidant, and Humic acid (HA). Experimental results revealed that HOCl and HSO5 can be catalyzed by NiSiOx but the HOCl has better performance than HSO5, HOCl was been chosen to be the oxidant of this research. Also when the concentration of MC-LR was 0.1μM, catalyst NiSiOx dosage was 1g/L, the optimized condition of MC-LR removal was 20μM HOCl and reaction pH was 7 without HA. Also the pathway of MC-LR oxidation were studied in this research.

[1] Andersen, J., et al. (2014). "Revealing the degradation intermediates and pathways of visible light-induced NF-TiO2 photocatalysis of microcystin-LR." Applied Catalysis B: Environmental 154-155: 259-266.
[2] Antoniou, M. G., et al. (2008). "LC/MS/MS structure elucidation of reaction intermediates formed during the TiO(2) photocatalysis of microcystin-LR." Toxicon 51(6): 1103-1118.
[3] Babuponnusami, A. and K. Muthukumar (2014). "A review on Fenton and improvements to the Fenton process for wastewater treatment." Journal of Environmental Chemical Engineering 2(1): 557-572.
[4] Burrows, C., et al. (1996). "Nickel catalyzed oxidations from hydrocarbons to DNA." Acta Chemica Scandinavica 50: 337-344.
[5] Antoniou, M. G., de la Cruz, A. A., Dionysiou, D. D. (2010). "Intermediates and reaction pathways from the degradation of microcystin LR with sulfate radicals." Environ Sci Technol 44: 7238-7244.
[6] Antoniou, M. G., Shoemaker, J. A., de la Cruz, A. A., Dionysiou, D. D (2008). "Unveiling new degradation intermediates pathways from the photocatalytic degradation of microcystin-LR." Environ Sci Technol 42: 8877-8883.
[7] Goodwin, D. C., et al. (1996). "Free Radicals Produced during the Oxidation of hydraazines by HOCl." Chem. Res. Toxicol 9: 1333-1339.
[8] He, X., et al. (2012). "Efficient removal of microcystin-LR by UV-C/H(2)O(2) in synthetic and natural water samples." Water Res 46(5): 1501-1510.
[9] J.P.ACornish, B., et al. (2000). "Hydrogen peroxide enhanced photocatalytic oxidation of microcystin LR using titanium dioxide." Applied Catalysis B: Environmental 25: 59-67.
[10] Jiang, W., et al. (2014). "Oxidation of microcystin-LR by ferrate(VI): kinetics, degradation pathways, and toxicity assessments." Environ Sci Technol 48(20): 12164-12172.
[11] Kim, M. S., et al. (2017). "Oxidation of microcystin-LR by ferrous-tetrapolyphosphate in the presence of oxygen and hydrogen peroxide." Water Res 114: 277-285.
[12] Lawton, I. L. L. A. and P. K. J. Robertson (2003). "Mechanistic studies of the photocatalytic oxidation of microcystin-LR An investigation of byproducts of the decomposition process." Environ Sci Technol 37: 3214-3219.
[13] Merel, S., et al. (2009). "Ms identification of microcystin-LR chlorination by-products." Chemosphere 74(6): 832-839.
[14] Miao, H. F., et al. (2010). "Detoxification and degradation of microcystin-LR and -RR by ozonation." Chemosphere 79(4): 355-361.
[15] Molina, L. T. and M. J. Molina (1987). "Production of Cl202 from the Self-Reaction of the CIO Radical." J. Phys. Chem 91: 433-436.
[16] Oakes, J. and P. Gratton (1998). "Kinetic investigations of the oxidation of arylazonaphthol dyes in hypochlorite solutions as a function of pH." J. Chem. Soc., Perkin Trans. 2: 2201-2206.
[17] Park, J.-A., et al. (2017). "Oxidation of microcystin-LR by the Fenton process: Kinetics, degradation intermediates, water quality and toxicity assessment." Chemical Engineering Journal 309: 339-348.
[18] Pud, A., et al. (1999). "The polyaniline poly(ethylene terephthalate) composite 1. Peculiarities of the matrix aniline redox polymerization." Synthetic metals 99: 175-179.
[19] Rodriguez, E. M., et al. (2008). "Oxidation of MC-LR and -RR with chlorine and potassium permanganate: toxicity of the reaction products." Water Res 42(6-7): 1744-1752.
[20] Sharma, V. K., et al. (2012). "Destruction of microcystins by conventional and advanced oxidation processes: A review." Separation and Purification Technology 91: 3-17.
[21] Sivey, J. D. and A. L. Roberts (2012). "Assessing the reactivity of free chlorine constituents Cl(2), Cl(2)O, and HOCl toward aromatic ethers." Environ Sci Technol 46(4): 2141-2147.
[22] Song, W., et al. (2006). "Ultrasonically Induced Degradation of Microcystin LR and RR   Identification of Products, Effect of pH, Formation and Destruction of Peroxides." Environ Sci Technol 40: 3941-3946.
[23] Stuart, J. N., et al. (2000). "Characterization of the Ni(III) Intermediate in the Reaction of (1,4,8,11 Tetraazacyclotetradecane)nickel(II) Perchlorate with KHSO5   Implications to the Mechanism of oxidative DNA modification." Inorg. Chem. 39: 5976-5984.
[24] Tang, W. W., et al. (2014). "Impact of humic/fulvic acid on the removal of heavy metals from aqueous solutions using nanomaterials: a review." Sci Total Environ 468-469: 1014-1027.
[25] Trifiro, G., et al. (2016). "Quantitative determination by screening ELISA and HPLC-MS/MS of microcystins LR, LY, LA, YR, RR, LF, LW, and nodularin in the water of Occhito lake and crops." Anal Bioanal Chem 408(27): 7699-7708.
[26] Wang, Q. Q., et al. (2015). "Growth of nickel silicate nanoplates on reduced graphene oxide as layered nanocomposites for highly reversible lithium storage." Nanoscale 7(40): 16805-16811.
[27] Yanfen, F., et al. (2011). "Unique ability of BiOBr to decarboxylate d-Glu and d-MeAsp in the photocatalytic degradation of microcystin-LR in water." Environ Sci Technol 45(4): 1593-1600.
[28] Yuan, B., et al. (2002). "Removal of cyanobacterial microcystin LR by ferrate oxidation coagulation." Toxicon 40: 1129-1134.
[29] Zhang, Y., et al. (2013). "Electrochemical degradation and mechanistic analysis of microcystin-LR." Journal of Chemical Technology & Biotechnology 88(8): 1529-1537.
[30] Zong, W., et al. (2013). "Oxidation by-products formation of microcystin-LR exposed to UV/H2O2: toward the generative mechanism and biological toxicity." Water Res 47(9): 3211-3219.
[31] 吳振齊 (2015). "製備雙邊開孔獨立二氧化鈦奈米管陣列薄膜用於光電化學偵測LR型微囊藻毒素."
[32] 林財富 (2016). "公共給水有害藻類及代謝物監測與緊急應變處理技術之研究." 經濟部.
[33] Machado, J., et al. (2017). "Effects of microcystin-LR and cylindrospermopsin on plant-soil systems: A review of their relevance for agricultural plant quality and public health." Environ Res 153: 191-204.
[34] Trifiro, G., et al. (2016). "Quantitative determination by screening ELISA and HPLC-MS/MS of microcystins LR, LY, LA, YR, RR, LF, LW, and nodularin in the water of Occhito lake and crops." Anal Bioanal Chem 408(27): 7699-7708.
[35] 胡宗億 (2007). "前臭氧於不同硬度水質下對微囊藻毒素-LR作用之探討."
[36] Ludwig, C., et al. (1996). "On the Mechanisms of Dissolution of Bunsenite [NiO(s)] and other simple oxide minerals" Journal of colloid and interface science 178(106): 176-185
[37] Molina, L. T., et al. (1986). "Production of Cl202 from the Self-Reaction of the CIO Radical” J. Phys. Chem. 1987, 91, 433-436