(552g) Cellulose Derived Mesoporous Magnetic Carbon Nanocomposites with Enhanced Cr(VI) Removal

Cr(VI) pollution is increasingly serious in surface water and groundwater due to its highly toxic for human health ^[1]. The cost effective and sustainable materials are urgently needed for the Cr(VI) removal. Cellulose is considered as a good adsorbent for for Cr(VI) removal due to its sustainability and abound active sites.But the low adsorption capacity and slow removal rate limit its application due to its small surface area and the lack of porosity. In this study, the newly magnetic carbons based on cellulose were fabricated through a simple calcination method.^[2] The properties of magnetic carbons synthesized by using the Fe₃O₄ nanoparticle and Fe(NO₃)₃ solution as the processors (MC-O and MC-N, respectively) were investigated. The materials were then used as the adsorbents for Cr(VI) removal from aqueous solution. Both Fe₃O₄ and Fe(NO₃)₃ were reduced to zero-valent Fe (ZVI) after calcination with cellulose at 800 ^oC. The MC-N exerts a higher proportion of ZVI and a bigger surface area and exhibits a better resistance against oxygen and acid than MC-O due to its smaller pore size. Both MC-O and MC-N present great performances on Cr(VI) removal. 4.0 mg/L Cr(VI) can be completely removed from neutral solution by both MC-O and MC-N within 10 min. Cr(VI) removal is highly pH-dependant, 1000 mg/L Cr(VI) can be completely removed in 10 min at pH 1.0. MC-O performs better than MC-N at pH 7.0, while MC-N presents a higher capacity than MC-O at pH 1.0. The magnetic carbons can be easily separated from solution by using permanent magnet after treated with Cr(VI). Finally, the Cr(VI) removal mechanisms including the Cr(VI) reduction and precipitation were discussed as well.

[1] Xu C., Qiu B., Gu H., et al. Synergistic Interactions between Activated Carbon Fabric and Toxic Hexavalent Chromium. ECS J. Solid State Sci. Technol., 2014, 3, M1-M9.

[2] Zhu J., Gu H., Guo J., et al. Mesoporous Magnetic Carbon Nanocomposite Fabrics towards Highly Efficient Cr(VI) Removal. J. Mater. Chem. A,  2014, 2, (7), 2256-2265.