Chiang Mai Journal of Science

Intercalated Zn-Cr-[α-SiW12O40] as Removal Agents of Cobalt (II) in Watery Phase: Adsorption and Regeneration Study

Paper Type	Contributed Paper
Title	Intercalated Zn-Cr-[α-SiW12O40] as Removal Agents of Cobalt (II) in Watery Phase: Adsorption and Regeneration Study
Author	Luna Silaen, Neza Rahayu Palapa, Elfita, Risfidian Mohadi and Aldes Lesbani*
Email	aldeslesbani@pps.unsri.ac.id
Abstract: The Zn-Cr layered double hydroxide was intercalated with polyoxometalate ion [α-SiW12O40]+ to form Zn-Cr-[α-SiW12O40]. Materials were characterized by X-Ray, FTIR, and nitrogen adsorptiondesorption and pH pzc analyses. Then materials were applied to remove cobalt(II) from in watery phase. Factors that affecting the adsorption included effect of adsorption time, initial concentration of cobalt(II), and adsorption temperature were systematically examined. The performance of Zn-Cr and Zn-Cr-[α-SiW12O40] were studied by regeneration process. The results showed that Zn-Cr layered double hydroxide has interlayer galley 7.53 Å. Zn-Cr-[α-SiW12O40] layered double hydroxide after intercalation has a unique diffraction peak at 8.62o with an interlayer gallery 10.35 Å; thus interlayer gallery increase 2.82 Å after the intercalation process. The surface area properties were also increased from 31.638 m2/g to 128 m2/g after intercalation. The pH pzc of Zn-Cr and Zn-Cr-[α-SiW12O40] layered double hydroxides were 7.5 and 8, respectively, and adsorption of cobalt(II) was conducted at these pH media. Adsorption of cobalt(II) on both adsorbents follows the pseudo second-order kinetic model and is categorized as physical adsorption in the range of energy 17.628-64.452 kJ/mol. Zn-Cr-[α-SiW12O40] follow the Langmuir isotherm model with an adsorption capacity is 45.45 mg/L at 303 K. That capacity is higher than Zn-Cr LDH, which has an adsorption capacity 30.39 mg/L at 303 K. Adsorption of cobalt(II) on layered double hydroxide was sharply decreased after three-time cycles due to sprayed and exfoliated of layered double hydroxide structure.
Start & End Page	545 - 556
Received Date	2020-07-28
Revised Date
Accepted Date	2020-10-04
Full Text	Download
Keyword	Zn-Cr, layered double hydroxide, intercalated, adsorption, cobalt, polyoxometalate, kinetic, thermodynamic
Volume	Vol.48 No.2 (March 2021)
DOI
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