Removal of heavy metals from wastewater using CFB-coal fly ash zeolitic materials

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• 作者：Nikolaos Koukouzas ; Charalampos Vasilatos ; Grigorios Itskos ; Ioannis Mitsis ; Angeliki Moutsatsou
• 关键词：CFB ; Coal fly ash ; Synthetic zeolites ; Water treatment ; Heavy metals
• 刊名：Journal of Hazardous Materials
• 出版年：2010
• 出版时间：15 January 2010
• 年：2010
• 卷：173
• 期：1-3
• 页码：581-588
• 全文大小：1698 K

文摘

Polish bituminous (PB) and South African (SA) coal fly ash (FA) samples, derived from pilot-scale circulated fluidized bed (CFB) combustion facilities, were utilized as raw materials for the synthesis of zeolitic products. The two FAs underwent a hydrothermal activation with 1 M NaOH solution. Two different FA/NaOH solution/ratios (50, 100 g/L) were applied for each sample and several zeolitic materials were formed. The experimental products were characterized by means of X-ray diffraction (XRD) and energy dispersive X-ray coupled–scanning electron microscope (EDX/SEM), while X-ray fluorescence (XRF) was applied for the determination of their chemical composition. The zeolitic products were also evaluated in terms of their cation exchange capacity (CEC), specific surface area (SSA), specific gravity (SG), particle size distribution (PSD), pH and the range of their micro- and macroporosity. Afterwards the hybrid materials were tested for their ability of adsorbing Cr, Pb, Ni, Cu, Cd and Zn from contaminated liquids. Main parameters for the precipitation of the heavy metals, as it was concluded from the experimental results, are the mineralogical composition of the initial fly ashes, as well as the type and the amount of the produced zeolite and specifically the mechanism by which the metals ions are hold on the substrate.