Zeolite NaA And NaX Synthesis From Fly Ash And Their Adsorption Of Heavy Metal Ions In Wasterwater

Single-phase NaA and -X zeolite were synthesized using fly ash as raw material by applying a two-step hydrothermal treatment process method in this paper. The synthesis parameters were investigated and optimized, and the resulting NaA and -X zeolite were used to adsorb heavy metal ions in electroplating wastewater. Through XRD expecting phase, SEM observing appearance, Malvern instrument analyzing granularity and the atomic absorption spectrophotometer and double dreams of light ultra absorption spectrophotometer measuring the concentrations of the heavy mental ions in the wastewater, the result showed that single-phase NaA and NaX zeolite could be synthesized as following conditions were used: NaOH concentrations, 1.67, 5 and 6.67mol/L; the synthesis temperature, 100℃and 120℃; the corresponding time, 340, 250 and 190 min. It was verified by the adsorption experiments that all these two kinds of zeolite could fast adsorpt the heavy mental ions such as Cu²⁺, Zn²⁺ and Cr(6+), and the sorption capacity of mental ions on zeolite NaA was larger than that on zeolite X. The adsorption kinetics of zeolite NaA for the mental ions were all corresponded to the modified pseudo-second-order equations, and the sorption isotherms all fitted the Langrnuir models. By calculating, the maximum sorption capacities of metal ions Cu²⁺, Zn²⁺ and Cr⁶⁺ on zeolite NaA were 82.37mg/g, 47.48mg/g and 65.92mg/g, respectively. During the adsorption process, these parameters, such as the particle size of zeolite, adsorbent dose, initial pH of solution, reaction temperature and contact time, play a important role in the removel efficiencies of the heavy mental ions. It was considered by the paper that the removel mechanism of the mental ions on the zeolite was by the adsorption and ion exchange processes.