Geopolymerization enhanced hydrothermal synthesis of analcime from steel slag and CFBC fly ash and heavy metal adsorption on analcime

ABSTRACT

This work is focused on crystal phase transition of solid wastes and functional application of crystal analcime in waste water purification, which provide a new environment-friendly route. In this paper, analcime was synthesized from steel slag and Circulating fluidized bed combustion (CFBC) fly ash (CFA) by hydrothermal method enhanced via geopolymerization (non-crystallized process). Then the analcimes were used for the removal of heavy metal ions (Pb²⁺, Cu²⁺) in aqueous solutions. Both the raw materials and products were characterized by XRF, XRD, FT-IR, SEM-EDS, and TEM. The results showed that non-crystallized process reduced the time of hydrothermal reaction and promoted the purity of analcime. The adsorption kinetics of analcime were all well fitted the pseudo-second-order model, and adsorption isotherms were well described by the Langmuir model. The maximum adsorption capacity of analcime for Pb²⁺ and Cu²⁺ were around 75.76, and 21.83 mg/g, respectively. The preference order observed for adsorption is Pb²⁺ > Cu²⁺.

GRAPHICAL ABSTRACT

KEYWORDS:

• Steel slag
• circulating fluidized bed combustion fly ash
• geopolymerization
• analcime
• heavy metal ions

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was financially supported by the National Key Research and Development Program of China [2017YFC0703203] and the Fundamental Research Funds for the Central Universities of China [2009KH09 and 2009QH02].