| Hydrothermal synthesis of zeolites-calcium silicate hydrate composite from coal fly ash with co-activation of Ca(OH)2-NaOH for aqueous heavy metals removalOA |
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| 引用本文： | Guanghui Li,Min Li,Xin Zhang,Pengxu Cao,Hao Jiang,Jun Luo,Tao Jiang. Hydrothermal synthesis of zeolites-calcium silicate hydrate composite from coal fly ash with co-activation of Ca(OH)2-NaOH for aqueous heavy metals removalOA[J]. 矿业科学技术学报(英文版), 2022, 32(3): 563-573. DOI: 10.1016/j.ijmst.2022.03.001 |
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| 作者姓名： | Guanghui Li Min Li Xin Zhang Pengxu Cao Hao Jiang Jun Luo Tao Jiang |
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| 基金项目： | supported by the National Natural Science Foundation of China (No. 52174273)；;the Basic Science Center Project for National Natural Science Foundation of China (No. 72088101)；;the Postdoctoral Science Foundation of China (No. 2021TQ0370)； |
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| 摘 要： | Coal fly ash is a typical secondary aluminum/silicon resource. The preparation of zeolite-type absorbent is a potential way for its value-added utilization, while the purity and adsorption property of zeolite are limited due to the occurrence of side reactions in the synthesis process. In this study, a designated composite consisted of crystalline zeolites and amorphous calcium silicate hydrate was selected, which was direct synthesized from fly ash under conditions of a Ca/Si molar ratio of 0.8...
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| 收稿时间： | 2021-08-09 |
Hydrothermal synthesis of zeolites-calcium silicate hydrate composite from coal fly ash with co-activation of Ca(OH)2-NaOH for aqueous heavy metals removal |
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| Affiliation: | School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China |
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| Abstract: | Coal fly ash is a typical secondary aluminum/silicon resource. The preparation of zeolite-type absorbent is a potential way for its value-added utilization, while the purity and adsorption property of zeolite are limited due to the occurrence of side reactions in the synthesis process. In this study, a designated composite consisted of crystalline zeolites and amorphous calcium silicate hydrate was selected, which was direct synthesized from fly ash under conditions of a Ca/Si molar ratio of 0.8, an initial NaOH concentration of 0.5 mol/L, a hydrothermal temperature of 170 ℃ and a liquid–solid ratio of 15 mL/g. The results indicated that this composite had superior adsorption property for a variety of heavy metals, which was based on the exchange of calcium and sodium ions in zeolites and calcium silicate hydrate. Its adsorption capacities for Pb2+, Ni2+, Cd2+, Zn2+, Cu2+ and Cr3+ attained 409.4, 222.4, 147.5, 93.2, 101.1 and 157.0 mg/g, respectively, in single solution with a pH of 4.5. After regulating the synthesis conditions, the transformation of amorphous calcium silicate hydrate into crystallized tobermorite weakened the adsorption capacity of the composite. Besides, due to the competitive adsorption in a multiple ions solution, the adsorption capacities for these heavy metals had a reduction. |
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| Keywords: | Coal fly ash Adsorption material Zeolite Calcium silicate hydrate Heavy metals |
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