| dc.description.abstract | Chromium, especially Cr6+, is a heavy metal that is often used in industry can pollute the aquatic environment, and has high toxicity for humans, therefore, Cr6+ must be removed from the aquatic environment. Mesoporous silica has a relatively small pore size and large surface area so it can be used as an adsorbent. However, the low effectiveness of silica in attracting metal means that silica must be modified, one of which is by adding nano Zero Valent Iron (nZVI) and nickel catalytic metal using the bimetallic impregnation method. Impregnation is carried out by mixing mesoporous silica (MS), iron (FeCl3.6H2O), sodium borohydride (NaBH4), and nickel (NiCl2.6H2O) with mass ratios of Fe:MS 1:1, 2:1, and 3:1, then applied to remove Cr6+. Impregnation products were analyzed by FT-IR, XRD, SEM-EDX, and BET. FT-IR analysis shows several peaks, namely at wavelengths 1624.43 cm-1 and 1334.67 cm-1, which are typical nZVI absorption bands. XRD analysis shows mesoporous peaks at 2θ 23.46° and nZVI at 2θ 44.6° and 62.8°. SEM-EDX analysis shows that Fe/Ni is distributed on the silica surface with the main constituent components namely 46.8% oxygen, 25.16% iron, 18.45% silica, 5.13% nickel, and 4.46% carbon. BET analysis showed a decrease in surface area from 260.15 m2/g to 249.38 m2/g, pore volume from 6.8588 nm to 4.333 nm, and average pore size from 0.6425 nm to 0.359 nm. Adsorption of Cr6+ using Fe/Ni-MS-TMR 1:1, 2:1, and 3:1 showed a change in color of the Cr6+ solution from yellow to pale yellow (1:1), slightly clear (2:1), and clear (3:1). The result is in accordance with the decrease in Cr6+ concentration detected by AAS analysis namely from 20 ppm to 16.56 (1:1), 6.20 (2:1), and, <0.01(3:1). The Cr6+ removal efficiency increased with the addition of Fe mass, namely 17.2% (1:1), 69% (2:1), and 99.95% (3:1). FT-IR analysis on Fe/Ni-MS-TMR 3:1 after presipitation of Cr3+ showed a typical Cr-O peak at a wavelength of 540.19 cm-1 and the Cr3+ solubility test on the adsorbent using NaOH produced a green solution, which proves that Cr3+ has been there on the adsorbent surface area. | en_US |
