LAUSR

In this study, expanded graphite (EG) by an environmentally friendly and mild oxidation intercalation and binary composite microbeads adsorbent (EG-xGel) was prepared to purify dye and oily wastewater. The synthesized EG and EG-xGel were characterized. A characteristic homogeneous dilation and vermicular structure with interconnected pores for EG and relatively uniform spherical with well dispersion for EG-64Gel were detected. Within 30 min, the adsorption amount of EG to engine and edible oil reached 23.89 and 26.03 g g–1, respectively. In the oily wastewater system, the corresponding amount increased slightly from 22.25 to 23.97 g g–1, and 26.38 to 30.92 g g–1 respectively, with the introduction of 15 g L–1 NaCl, which might be due to the higher ionic strength reduced the solubility of the adsorbate in the solution. The highest removal of 68.2% and 87.2% was observed for 50 mg L–1 methylene blue (MB) at the original pH for 2 h and congo red (CR) at pH 3 for 40 min, respectively, with 0.1 g EG-64Gel microbeads by air dried applied at room temperature. The pseudo-second-order kinetics described MB and CR adsorption process better. Moreover, EG-64Gel exhibited excellent separation performance under acidic condition with CR dye almost removed completely in the binary MB/CR system. All these results indicated that EG and EG-xGel are expected to be promising candidates for the frequent oil-spill accidents and dye wastewater pollution.