WALAILAK JOURNAL OF SCIENCE AND TECHNOLOGY

Volume 18, No. 10, Month MAY, Year 2021, Pages -

Removal of malachite green dye using keggin polyoxometalate intercalated znal layered double hydroxide

Aldes LESBANI, Tarmizi TAHER, Neza Rahayu PALAPA, Risfidian MOHADI, Mardiyanto, Miksusanti, Fitri Suryani ARSYAD

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The ZnAl Layered double hydroxides (LDHs) have been successfully synthesized by the coprecipitation method, followed by intercalation using Keggin ion of α-dodecatungstosilicic acid [α-SiW12O40]4- to form ZnAl-[α-SiW12O40] LDHs. The prepared ZnAl-[SiW12O40] LDHs were characterized by using X-Ray, FTIR, and BET surface area analyses, which were, then, used as adsorbents of malachite green dye from aqueous solution. The synthesized ZnAl LDH showed a typical diffraction peak of the layered compound at 11o (003) with an interlayer space of 8.59 Å. After intercalation, it was recorded that the interlayer space of ZnAl-[SiW12O40] LDH increased to 10.65 Å. Moreover, the specific surface area of the intercalated LDH increased from 1.9685 to 14.0422 Å. The adsorption study revealed that the adsorption capacity of ZnAl-[SiW12O40] LDH toward malachite green dye was higher (37.514 mg.g-1) than the pristine ZnAl LDH (32.845 mg.g-1). The adsorption kinetics study showed that malachite green adsorption onto both pristine and intercalate LDH followed the pseudo-2nd-order model. The adsorption thermodynamic investigation indicated that adsorption of malachite green onto ZnAl-[SiW12O40] LDH was a spontaneous process and was classified as physical adsorption with activation energy ranging from 10.074 to 15.476 kJ.mol-1.

Keywords

Malachite green, Layered double hydroxides, Zn/Al, Keggin ion, X-Ray, Polyoxometalate

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