In this study, the mixture of zinc acetate dehydrates and boric acid was pyrolyzed in zeolite X to prepare novel B/ZnO/zeolite nanocomposites for the enhanced removal of tartrazine (TA) in aqueous environment. The composites are porous material with a relatively large pore size (35.3 nm). The surface area of the composite (19.72 m2/g) is smaller than that of zeolite (248.78 m2/g), but its adsorption capacity is quite high (qmax of 89.0 mg/g). The factors influencing the adsorption process were investigated in detail. Under the optimal conditions (the initial dye concentration of 20 mg/L, the adsorbent content of 0.5 g/L, pH = 6, and the temperatures of 25 ℃), the removal efficiency (Re) was 97.5 %. The first and second-order equations were used to model the kinetic adsorption. The Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich models were used to study isothermal adsorption. In addition, the thermodynamic of adsorption was also investigated. The ∆Ho of -56.219 kJ.mol-1 indicates the exothermic process and the negative ∆Go indicates a spontaneous process. At low temperatures, the adsorption of TA proceeds smoother and more effectively, and the negative ∆So (-142.036 J.mol-1.K-1) indicates a decrease in the degree of freedom of the adsorbed species. The adsorption mechanism was also proposed.
Keywords: Adsorption; B/ZnO/zeolite; Composite; Pyrolysis; Tartrazine.
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