Abstract
•Zeolite–activated carbon (Z–AC) composite was synthesized with oil palm ash as precursor.•The adsorption process was well supported by kinetic and isothermal models.•The adsorption capacity of Z–AC for MB was superior to similar types of adsorbents.•The Z–AC composite represents low-cost composites as adsorbents for dye removal.
A mesoporous high-surface-area zeolite–activated carbon (Z–AC) composite was prepared by chemically facilitated NaOH activation and hydrothermal treatment with oil palm ash as substrate. The prepared Z–AC composite was characterized by X-ray diffraction, Fourier transform infrared spectroscopy, BET surface area and pore structural analysis, and scanning electron microscopy. The adsorption performance of Z–AC for methylene blue (MB) removal was examined using a batch method. The effects of initial dye concentration (25–400mg/L), temperature (30°C–50°C), and pH (3–13) on the adsorption of MB on Z–AC were studied. Pseudo-second-order kinetics was found to describe the adsorption process better than pseudo-first-order kinetics. Freundlich and Langmuir isotherms applied on the adsorption data reveal that data best fitted Freundlich model. The maximum adsorption capacity values of the Z–AC composite for MB were 143.47, 199.6, and 285.71mg/g at 30, 40, and 50°C, respectively. These results show that the Z–AC composite could provide basis for more low-cost composites to be used as adsorbents for dye removal.
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