Graphene oxide (GO) has received significant interest as a platform material for environmental engineering applications, including sorption and catalysis for remediation technologies, based on a number of unique physico-chemical properties, relative ease of synthesis, and low material cost(s). GO materials typically have extremely large surface area(s) because of its single layer morphorogy with excellent mechanical and chemical resistance of the honeycomb carbon backbone structure. Further, due to the presence of oxygen-based functional groups, GO can be broadly (surface) modified by inorganic and organic materials. In this presentation, we will describe the critical role of the polyethylenimine (PEI) for Cr(VI) removal, and PEI functionalized GO (GO@PEI) for Cr(VI) sorption/separation and photoreduction as a function of light intensity, pH, and PEI surface loading. The potential loading capacity of PEI on the surface of the GO increased with the oxidation degree of GO and the MW of PEI. The highest PEI loaded GO showed the best Cr(VI) sorption and photoreduction performance under UV and dark conditions. The maximum sorption density was found to be 217.4 mg/g at pH 3 and the pseudo first order photoreduction rate constant was 1.72 h<sup>-1</sup><sup> </sup>at pH 5; sorption was rapid and at equilibrium within 5 min. Lastly, GO@PEI maintained its initial Cr(VI) sorption capacity over five cycles in the dark, indicating potential for material reuse / recycling.

PEI functionalized graphene oxide for enhanced sorption and rapid photoreduction of chromium (VI)

255th National Meeting (2018)

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