Carbon microfibers with tailored surface functionalities supporting iron/nickel bisalloy for highly efficient hexavalent chromium recovery

摘要

Carbon microfibers with a tailored surface functionality supporting iron/nickel bisalloy (FeNi@CMFs) have been successfully prepared in a single step by electrospinning combined with high temperature annealing method at an optimal condition: 5 wt% mass fractions of metal salts (ferric nitrate and nickel nitrate) annealed at 800 degrees C for 60 min in 5% (v/v) hydrogen/argon atmosphere. By simply controlling the microstructures and surface functional groups of CMFs in FeNi@CMFs through mass fractions of metal salts, annealing temperature and annealing time, FeNi@CMFs could acquire an outstanding ability to efficiently reduce hexavalent chromium (Cr(VI)) to trivalent chromium (Cr(III)) by iron/nickel bisalloy and simultaneously adsorb Cr(III) by carboxyl groups on the CMFs through chelation. The Cr(VI) removal by FeNi@CMFs follows the pseudo-second-order model. In thermodynamics, the negative Delta G(0) and positive Delta H-0 reveal that the Cr(VI) removal by FeNi@CMFs is a spontaneous and endothermic process, meaning that the increase in temperature is favorable for the Cr(VI) removal. Consequently, FeNi@CMFs are a kind of novel and efficient materials for Cr(VI) remediation. (C) 2020 Elsevier Ltd. All rights reserved.