Exploring the Iron Oxide Functionalized Biobased Carbon-silica-polyethyleneimine Composites for Hexavalent Chromium Removal from Dilute Aqueous Solutions

The contamination of water resources by toxic hexavalent chromium remains a challenge. In this study, amino-functionalized iron oxide biobased carbon-silica composites were prepared through co-precipitation of Fe(II) and Fe(III) over <i>Macadamia</i> activated carbon and explored as feas...

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Autores principales: Mpho Cynthia Qhubu, Philiswa Nosizo Nomngongo, Vusumzi Emmanuel Pakade
Formato: article
Lenguaje:EN
Publicado: MDPI AG 2021
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Acceso en línea:https://doaj.org/article/f402f003ed6e479cb6749af723c47013
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Sumario:The contamination of water resources by toxic hexavalent chromium remains a challenge. In this study, amino-functionalized iron oxide biobased carbon-silica composites were prepared through co-precipitation of Fe(II) and Fe(III) over <i>Macadamia</i> activated carbon and explored as feasible adsorbents for the removal of Cr(VI) from dilute aqueous solutions. The energy dispersive spectroscopy (EDS) elemental analysis confirmed the existence of Fe, Si, O, and C atoms, which form the backbone of the composite. The FTIR also showed the presence of Fe-O and Si-O-Si and Si-OH spectral bands, affirming the backbone of the adsorbents. Cr(VI) adsorption efficiency (5.76 mg/g) was achieved at pH 1 when an initial concentration of 2.5 mg/L, contact time of 90 min, and dosage concentration of 1.7 g/L were used. The data were best described by the Langmuir adsorption model and pseudo-second-order rate model. Δ<i>G</i>° (−3 to −12 kJ/mol) and Δ<i>H</i>° (46, 12 and 5 kJ/mol) values affirmed that the adsorption of Cr(VI) was spontaneous and endothermic and dominated by chemical interactions.