燃煤飛灰可再利用作為廢水廢氣處理過程中之吸附劑。燃煤飛灰顆粒細小但其表面積較大，許多研究以燃煤飛灰作為吸附劑去除水中之污染物的探討。燃煤飛灰的來源不同也有會產生不同的物理化學特性。如燃燒條件、飛灰集塵設備及飛灰的產源等都會造成差異。本研究採取燃煤飛灰再以高溫爐鍛燒於550C˚脫碳製成不同含碳量飛灰作為吸附劑，以腐植酸作為吸附質，進行回分式吸附實驗，分別探討不同含碳量、不同時間及不同吸附劑添加量對腐植酸吸附去除之影響。研究發現飛灰之比表面積隨著含碳量增加而增加，且在不同腐植酸濃度、吸附反應時間、吸附劑量等條件下，不同燃煤飛灰對腐植酸之去除率皆隨著飛灰中所含碳量的增加而遞增。本研究結果可提供燃煤飛灰再利用為吸附參考。 Fly ash generated from coal burn power plant caused a disposal problem. Fly ashes are now used to partially replace cement in construction. Some investigations have reported that fly ashes can can also serve as adsorbents for wastewater treatment or air pollutant control.
The feasibility of regenerating fly ash as an adsorbent has been discussed previously, and qualitative information on pollutant removal and the chemical constituents of fly ashes obtained from various power plants has been reported. However, the removal efficiencies of organic pollutants using fly ashes as adsorbents varied, according to the characteristics of the fly ash and the status of adsorption experiments.
In this study, fly ashes with different quantities of carbon and minerals prepared by a thermal process in the laboratory were used as adsorbents to investigate the effect of carbon content in the fly ash on the removal of humic acid. Batch adsorption experiments are also conducted to evaluate how carbon and mineral fraction of fly ashes contributes to surface adsorption. Experimental results showed that the specific surface area of fly ash increased linearly with the quantity of carbon. The specific surface areas of the carbon and mineral fraction determined by linear regression were 60 m2/g and 0.68 m2/g, respectively. Meanwhile, the specific adsorption capacities of carbon ranged from 5.20~11.06mg/g carbon, while those for mineral were only about 1.98 to 3.09 mg/g mineral. It was found the carbon fraction of the fly ash is a very significant parameter for the removal of humic acid. This variable influenced the specific surface area of the fly ash, and thus determined the removal efficiency of humic acid.