燃煤飛灰中之礦物組成特性受燃煤種類影響而不同，飛灰中礦物組成影響其對水中銅離子之單位吸附量，不同礦物組成含量之燃煤飛灰對水中銅離子吸附量之單位吸附量最大差距可達16倍，其中又以氧化鐵及氧化矽之含量對吸附水中銅離子吸附量之影響最為顯著。
因不同金屬氧化物(具不同之零電位點，當溶液pH高於燃煤飛灰中特定金屬氧化物之PZC (point of zero charge)時，其表面帶負電荷；而當溶液pH低於燃煤飛灰中特定金屬氧化物之PZC時，其表面帶正電荷。因此，本研究擬外加電磁場環境下，改變並調整燃煤飛灰溶液之pH值，控制燃煤飛灰中特定金屬氧化物之帶電特性，使燃煤飛灰顆粒依帶電粒子移動方向及磁場方向構成平面之垂直方向而移動，達到分選金屬氧化物之成效。最後，藉著探討產物物理化學特性及其吸附水中銅離子成效之關係，評估以電磁場分選燃煤飛灰中金屬氧化物作為廢水吸附劑之可行性。
研究結果發現，控制在不同pH條件下時，飛灰中Al2O3及SiO2含量增加，而經由磁場分選後之產物，其比表面積有增加的趨勢，由1.05(m2/g)可增加到2.65(m2/g)。而在吸附水中銅離子方面，產物之單位吸附量可達到2.11( mg-Cu2+ / g-fly ash )。在絕對回收率方面，pH值越高所回收的燃煤飛灰產物其絕對回收率也較高，而當磁場強度增加時，其回收率也會增加，通過2.5A之電磁場分選燃煤飛灰在控制pH10時，其絕對回收率為82.2% 。而在陽離子交換容量(Cation exchange capacity，CEC)方面，單獨控制在不同pH條件下時，產物之CEC則有隨pH值增加而增加的趨勢。本研究中所獲得之實驗數據可提供做為後續電磁場分選燃煤飛灰條件最佳化之參考。 An effective solution to the problem is in demand. According to the finding in the study, the specific adsorption capacity（SAC）of copper ions using fly ashes with different mineral compositions as adsorbents varied violently. It was found that the SAC of fly ash in adsorbing copper ion was in the range of 0.12 and 1.87（mg Cu2+ / g fly ash）and correlated with the mineral composition of Fe2O3 and SiO2 in the coal fly ashes.
The metal oxides in the fly ashes with different point of zero charge（PZC）carry positive or negative charge according to the solution pH. When the pH of the solution is higher than the PZC of the metal oxide, the charge on the surface of the oxide is negative. On the other hand, the charge on the surface of the oxide is negative, when the pH of the solution is higher than the PZC. In this search, the coal fly ash was gathered from power plant. Iron oxides in fly ash will be specified separated from other minerals by means of electric-magnetic separation system（EMSS）developed in this study. Substances from EMSS were collected as adsorbents and were applied to adsorb copper ions from aqueous solution in the adsorption experiment. Finally, the feasibility of iron oxides specified separated by EMSS will be discussed in detail.
Research result shows that the Al2O3 and SiO2 content in separated products increased when PH was control at 4、7、10. The BET of products from EMSS, increased from 1.05(m2/g) to 2.65(m2/g). The specific adsorption capacity of copper ions was 2.11( mg-Cu2+ / g-fly ash ). In addition, the absolute recovery rate of fly ash increased with solution pH and intensity of magnetic field. CEC of the separated products remained unchanged. However, when fly ashes soaked in aqueous solution, CEC of fly ashes increased with solution pH.
