Graphene composites as dye adsorbents: Review

One of the most important decontamination techniques is considered to be adsorption. It is fast, simple, low-cost with many opportunities to modify the initial materials after appropriate synthesis routes etc. Numerous adsorbent materials are prepared the last years having as ultimate scope to remove some toxic pollutants especially from contaminated waters (effluents originated from industries). But the composition of each type of effluents is varying. Dyes are some major components of industrial wastewaters. In the last years, graphene attracted many researchers employing with adsorption technique, because of its excellent properties and two-dimensional structure. Researchers started to synthesize more effective graphene adsorbents making some additions to initial structure, preparing many graphene composites. This review summarizes the important contribution of graphene composites to adsorption technique. Many preparation routes of graphene composites are given along with the respective characterization techniques, properties of the materials, and of course detailed adsorption evaluation of graphene composites. The latter is based on some adsorption parameters as maximum adsorption capacity, kinetic behavior, thermodynamics, and possible reuse ability. The data clearly demonstrate that the adsorption capacity of graphene composites is very high (up to 1300 mg/g depending on the dye molecule). The majority of works has been successfully fitted to Langmuir isotherm model and pseudo-second order kinetic equation. To highlight the superiority of graphene composites, comparison with other adsorbents is mandatory. This work summarizes the very recently published works of the last years. (C) 2017 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.