燃煤飛灰（Coal Fly Ash）是燃煤發電廠之主要副產物，每年因發電所產生之大量飛灰，往往在處理處置上常造成極大之困擾，亟待尋求有效解決方案。飛灰為玻璃圓球狀之細小微粒，釵h研究應用其具有較大表面積之特性作為去除水中污染物之吸附劑。然而，飛灰之物理、化學特性受煤碳成份、燃燒條件及防制設備等因素之影響，而極大之差異導致在應用飛灰去除各種污染物時之變動甚鉅。因此，須積極釐清飛灰之組成特性對去除水中污染物之影響，俾利應用飛灰進行污染物之控制。而根據前人之研究成果發現飛灰中所含之未燃碳為去除水中銅離子之主要因素，且其單位吸附量為礦物組成之3~4倍。然而，當飛灰中所含未燃碳除去之後，所剩下之礦物組成（如氧化矽、氧化鋁、氧化鐵、氧化鈣、氧化鎂及其它項）對吸附水中銅離子之影響尚無相關之論著，亟待深入探討。本研究將燃煤火力發電廠飛灰及經破碎之煤碳，經550℃高溫鍛燒24小時，將所含之未燃碳去除後，分析飛灰礦物組成、比表面積、陽離子交換容量、粒徑分析、晶相結構及飛灰表面之顯微外觀等，並進行恒溫吸附試驗計算飛灰對水中銅離子之單位吸附量（mg-Cu2+ /g-fly ash）。最後，藉由多元線性迴歸統計分析（multiple linear regression，MLR）建立不同礦物組成飛灰吸附水中銅離子之單位吸附量預測模式。研究結果發現，Fe2O3及SiO2對吸附水中銅離子之貢獻最顯著，此外，藉多元線性迴歸所建立之以礦物組成預測單位銅離子之吸附量模式為Y（mg-Cu2+ / g-fly ash）= 9.994×Fe2O3＋0.673SiO2，其複判定係數R2=0.908；經由開方轉換後之預測模式Y（mg-Cu2+ / g-fly ash）=（4.854×Fe2O3＋0.857×SiO2＋0.989×Other＋0.818×CaO）2，複判定係數R2＝0.969。本研究所建立之預測模式可提供做為選擇燃煤飛灰作為水中重金屬吸附劑之參考。 Coal fly ash is the main byproduct of coal-fired power plants. The large amount of fly ash from processes of electrical energy generation has caused enormous problems of disposal. An effective solution to the problem is in demand. Fly ash is made of glass spherical tiny particles. Researches make use of fly ash’s distinct surface area as the adsorbent for the removal of water pollutant. However, its physical and chemical properties and its composition are greatly influenced by the proportion of carbon, conditions of combustion and air pollution control equipment. The characteristics of fly ash particles also have a great impact on the removal efficiency of aqueous pollutants. Therefore, it is essential to verify the composition of fly ash for the determination of pollutants removal efficiency. Previous studies indicate carbon was the main factor in removing copper ion from aqueous solution. The adsorption capacity of carbon is 3~4 times greater than that of component minerals. However ,Whether the minerals (e.g. SiO2、Al2O3、Fe2O3、CaO、MgO, etc.) of the fly ash affects the adsorption of aqueous copper ions have not been discussed. This research calcined the fly ash from coal-fired power plant at 550 oC for 24 hours to remove the carbon residue. The component minerals ,BET,CEC, distribution of particle size of the fly ash were examined.The laboratory-prepared fly ashs were made from pulverized coal baked at the same comdition as thermal process of the fly ash.The adsorption isotherm experiments were conducted the removal process of the evaluate the specific adsorption capacity of copper ions (mg- Cu2+/g-fly ash).Finally, prediction models of Cu2+ adsorption capacity of fly ashes with various minerals composition were developed by multiple liner regression, (MLR). Research results demonstrates Fe2O3 and SiO2 adsorb more copper ion from aqueous solution than others. Besides, the prediction model of specific adsorption capacity of copper ion is Y (mg-Cu2+/g-fly ash)=9.994×Fe2O3 + 0.673 ×SiO2, with coefficient of determination R2=0.908. Obtain the prediction model through evolution transformation: Y (mg-Cu2+/g-fly ash)=(4.854×Fe2O3+0. 857×SiO2+0.989×other+0.818×CaO)2, Coefficient of Determination R2=0.969.The prediction models developed in this study can be helpful for the selection of coal fly ash as the adsorbent of heavy metals from aqueous solution.
