| Abstract:
In the current study, zeolitic imidazolate framework-8 (ZIF-8) was used as a new absorbent to investigate adsorption of arsenic ion from aqueous solution. ZIF-8 crystals were successfully synthesized via hydrothermal method by applying the temperature factor. The ZIF-8 crystals were characterized by nitrogen adsorption– desorption, powder X-ray diffraction, scanning electron microscope, and Fourier transform infrared spectroscopy. Different parameters such as metal ions concentration, adsorbent dosage, contact time, and pH were evaluated in adsorption experiments. The adaptation of adsorption process was analyzed by Langmuir, Freundlich, pseudo-first-order, and pseudo-second-order models of types1-4. The specific surface area of ZIF-8 is based on BET equation of 1303 m2/g and the particle size was 70-150 nm. The kinetic and isotherm data of arsenic adsorption on ZIF-8 were well fitted by pseudo-second-order Kinetics model of type 2 and Langmuir model, with regression values of 0. 963 and 0. 979, respectively. In optimum condition the maximal adsorption capacity of arsenic was 69. 36 mg/g. The results indicate that ZIF-8 has high ability to absorb arsenic ion without having need to adjust pH solution for most water treatment.
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