NiFe-LDH nanosheet/carbon fiber nanocomposite with enhanced anionic dye adsorption performance

Excessive discharge quantity of toxic dyes has been confirmed to be detrimental to the ecological system and human health. Thus, an effective adsorbent must be developed to remove toxic dyes from wastewater. Herein, NiFe-layered double hydroxide (LDH) (NiFe-LDH) nanosheets are successfully grown on carbon fiber prepared using a facile one-pot hydrothermal route, which can integrate the advantages of carbon fiber and NiFe-LDH nanosheets. The as-prepared C/NiFe-LDH composite exhibits high specific surface area, hierarchical porous structure, and positive surface charge. These characteristics are beneficial for removing methyl orange (MO) and Congo red (CR) anionic dye. Kinetic data of MO and CR adsorbed onto as-prepared samples match well with those of pseudo-second-order model. Adsorption isotherms effectively fit Langmuir isotherm model. The Langmuir isotherm model indicates that the maximum adsorption capacities of MO and CR on the C/NiFe-LDH composite are 323.6 and 448.4 mg g⁻¹, respectively, at 30 °C. These results are much higher than those of pure carbon fiber and NiFe-LDH. The synthesized C/NiFe-LDH is recyclable. Therefore, the C/NiFe-LDH composite can be a potential candidate for removing MO and CR in wastewater treatment given its facile synthesis method and excellent adsorption performance. Copyright © 2020 Elsevier B.V. All rights reserved.