SINTESIS HIDROKSI LAPIS GANDA Ni/Fe DAN Ni/Fe TERINTERKALASI SENYAWA POLIOKSOMETALAT K4[α-SiW12O40]·nH2O SERTA APLIKASINYA SEBAGAI ADSORBEN Fe(II) DAN Cr(VI)
Daftar Isi:
- Synthesis of Ni/Fe layered double hydroxide and Ni/Fe intercalated by polyoxometalate compound of Keggin type K4[α-SiW12O40]·nH2O was successfully synthesized. Characterization of synthesized material using XRD analysis, FT-IR, and Brunaeur Emmet Teller (BET) surface area analysis. The synthesized material was applied as adsorbent Fe(II) and Cr(VI). The results of XRD diffractogram analysis of Ni/Fe layered double hydroxide were successfully synthesized which showed an angle of 2θ at 11.53 ̊ with an interlayer space 7.668 Å and an increase in interlayer space of Ni/Fe layered double hydroxide intercalated to 10.78 Å. The BET analysis results showed that the surface area of Ni/Fe layered double hydroxide was 18.2525 m2/g and an increase in the surface area of Ni/Fe layered double hydroxide intercalated to 56.6288 m2/g. The FT-IR spectrum shows the Ni/Fe layered double hydroxide was successfully synthesized with a vibration at 1381 cm-1 (υNO3-) and Ni/Fe layered double hydroxide intercalated with characteristic vibration of K4[α-SiW12O40]·nH2O at 1200-900 cm-1 (υW=O) and 850-700 cm-1 (υW-O-W). The determination of pH point zero charge synthesized material shows that Ni/Fe layered double hydroxide at pH 9 and Ni/Fe layered double hydroxide intercalated at pH 7. The synthesized material was applied as adsorbent of Fe (II) and Cr (VI) with variety of conditions, such as time, temperature and concentration. The kinetic adsorption parameters show that Ni/Fe layered double hydroxide and Ni/Fe layered double hydroxide intercalated as adsorbent of Fe(II) follows pseudo second order kinetic model with k2 value of Ni/Fe layered double hydroxide is 0.00166 g/mg.min-1 who greater value than k2 Ni/Fe layered double hydroxide intercalated is 0.00164 g/mg.min. The adsorption rate of Ni/Fe layered double hydroxide as Cr(VI) adsorbent follows pseudo first order kinetic model and adsorption rate of Ni/Fe layered double hydroxide intercalated as Cr(VI) adsorbent follows pseudo second order kinetic model with the k1 value of Ni/Fe layered double hydroxide is 0.084 g/mg.min-1 and k2 value of Ni/Fe layered double hydroxide intercalated 0.001 g/mg.min. The results of adsorption isotherm show that Langmuir adsorption isotherm is better for explaining the Fe(II) adsorption process (monolayer) and Freundlich isotherm model is better for explaining the Cr(VI) adsorption process (multilayer). The thermodynamics adsorption parameters show that the adsorption process of Fe(II) and Cr(VI) is endothermic and more spontaneous at higher temperature.