Synthesis of zeolites X and A from fly ashes for cadmium and zinc removal from aqueous solutions in single and binary ion systems
Synthesis of zeolites X and A from fly ashes for cadmium and zinc removal from aqueous solutions in single and binary ion systems
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DOI：
10.1016/j.fuel.2012.07.060
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发表时间：
2013-01-01
期刊：
影响因子：
7.4
通讯作者：
Wang, Shaobin
中科院分区：
文献类型：
--
作者：
Izidoro, Juliana de C.;Fungaro, Denise A.;Wang, Shaobin
以两种不同的巴西粉煤灰为原料，采用两步法选择性合成了纯X和A型沸石。采用XRD、SEM、BET、CEC等测试手段对沸石进行了表征。XRD和SEM结果表明，从粉煤灰中得到的X和A分子筛具有较高的阳离子交换量（3.1- 3.9meq/g）。用纯X和纯A沸石对锌和镉进行了单组分和双组分吸附。吸附研究表明，锌更优先吸附在纯沸石比镉在单一和二元系统在相似的实验条件下。沸石-A表现出比沸石-X更高的吸附。吸附等温线符合Langmuir模型。在单、二元离子体系中，纯沸石对锌和镉的吸附容量分别为156-220 mg/g和57-195 mg/g。与X型沸石不同，A型沸石对两种离子的去除受竞争离子的影响较小。(C)2012爱思唯尔有限公司保留所有权利。
Two different Brazilian fly ashes were used to selectively synthesize pure zeolites X and A by a two-step process. The zeolites were characterized in terms of mineralogical composition (XRD), morphological analysis (SEM), specific surface area (BET method), and cation exchange capacity (CEC). XRD and SEM results indicated that pure zeolites X and A were obtained from fly ash samples, possessing high CEC at 3.1-3.9 meq/g. The pure zeolites X and A were used in adsorption of zinc and cadmium in single and binary systems. The adsorption studies showed that zinc is more preferentially adsorbed on pure zeolites than cadmium in both single and binary systems under similar experimental conditions. Zeolite-A presented higher adsorption than zeolite-X. The adsorption isotherms followed the Langmuir model. The adsorption capacities for zinc and cadmium on the pure zeolites ranged 156-220 mg/g and 57-195 mg/g in the single and binary ion systems, respectively. The removal of both ions by zeolites A was less affected by the presence of a competitive ion, different from zeolites X. (C) 2012 Elsevier Ltd. All rights reserved.