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Journal : IJEMS (Indonesian Journal of Environmental Management and Sustainability)

Modification Of Zn-Cr Layered Double Hydroxide With Keggin Ion [?-SiW12O40]4- AS Cr(VI) Adsorbent Melantina Melan Oktriyanti; Neza Rahayu Palapa; Risfidian Mohadi; Aldes Lesbani
Indonesian Journal of Environmental Management and Sustainability Vol. 3 No. 3 (2019): September
Publisher : Research Centre of Inorganic Materials and Complexs

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (984.079 KB) | DOI: 10.26554/ijems.2019.3.3.93-99

Abstract

Abstract: In this study, synthesis of layered double hydroxide of Zn-Cr and Zn-Cr intercalated with keggin ion [SiW12O40]4- have been carried out. The synthesized material was characterized using XRD, BET, and FTIR. Material of Zn-Cr layered double hydroxide and the intercalation results are used as Cr(VI) ion adsorbent. Factors that influence the adsorption process studied to obtain kinetic and thermodynamic parameters include time, concentration and temperature variation of adsorption. Based on XRD characterization, the distance between layers from 7,53 ? on the Zn-Cr layered double hydroxide before intercalation to 10,26 ? on Zn-Cr layered double hydroxide intercalated with keggin ion [SiW12O40]4-. BET analysis showed that the surface area of both materials increased from 31,638 m2/g to 128,871 m2/g. The result of pH Point Zero Charge measurement for the Zn-Cr layered double hydroxide material is 10 while the Zn-Cr intercalated with keggin ion [SiW12O40]4- material is 8. Based on the kinetics model, adsorption of Cr(VI) ion follows pseudo-second-order model with a linear regression coefficient close to 1. Furthermore, the intercalation of the Zn-Cr intercalated with keggin ion [SiW12O40]4- shows the higher adsorption capacity for the Cr(VI) ion than the Zn-Cr layered double hydroxide as a control. Keywords: adsorption, Cr(VI), keggin ion, layered double hydroxide, Zn-Cr
Performance of Graphite for Congo Red and Direct Orange Adsorption Rananda Vinsiah; Risfidian Mohadi; Aldes Lesbani
Indonesian Journal of Environmental Management and Sustainability Vol. 4 No. 4 (2020): December
Publisher : Research Centre of Inorganic Materials and Complexs

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26554/ijems.2020.4.4.125-132

Abstract

To investigate its ability, graphite material was characterized by X-Ray diffraction (XRD), Fourier Transform Infrared Spectrophotometer (FTIR), Thermo Gravimetry Differential Thermal Analyse (TG-DTA), and Brunauer Emmet Teller (BET). Adsorption capability was evaluated by using Congo Red dye and Direct Orange dye solutions. The experiment was studied by using kinetic, isotherm, and thermodynamic parameters. The result of XRD characterization showed that graphite has four characteristic peaks which are 26,405?(002), 44,50?(101), 54,45?(004), and 77,32?(006). FT-IR characterization showed that the vibration at 3402 cm-1, 1635 cm-1, and 1381 cm-1. TG-DTA analysis showed that graphite has only one decomposition peak at 760 oC. BET analysis showed that the surface area of graphite was 11,558 m2/g. The optimum pH of CR and DO dyes were in pH 6 and pH 2 with contact time of 120 minutes.  Kinetic adsorption model of CR and DO dye onto graphite follow pseudo-second-order model with a liner regression coefficient close to one. Isotherm parameter of CR and DO adsorption onto graphite follow Langmuir isotherm model with spontaneous endothermic process. The desorption process of graphite was used HCl to remove the dyes.  Regeneration process of graphite showed that the capacity of adsorption decreased after it was reused 3 times.