▎ 摘　　要

Nano-scale graphene has been employed to remove dye pollutants in wastewater treatment. However, engineering concerns associated with inconvenient recollection of nano-graphene and bio-toxicity to human cells significantly hampered its application for environmental protection. In this study, monolithic form of graphene was fabricated by urea assisted self-assembly protocols and applied as an adsorbent to remove model organic pollutant, methylene blue dye (MB). The fabricated material was characterized by scanning electron microscopy (SEM), Fourier transmission infrared spectroscopy (FT-IR), Raman spectroscopy, and X-ray photo electron spectroscopy (XPS), Thermogravimetric analysis (TGA) and nitrogen adsorption-desorption isotherms. Characterization results show that graphene monolith with tailored macroscopic dimension, highly porous network and active binding sites (e.g., functional groups and aromatic domains) could provide facile mass transfer of pollutant and cost-effective recollection. Adsorptive removal of MB best suited to Langmuir isotherm, pseudo-second-order kinetics, and intra particle diffusion kinetics models. Complete removal of MB (>98%) was achieved under optimum conditions (e.g., alkaline pH, 160 mM of salt and 1 g/L adsorbent dose at 25 degrees C). Removal of MB using monolith was favorable, spontaneous and exothermic adsorption process. Electrostatic and pi-pi staking interactions were identified as major interaction process. A monolithic form of graphene demonstrates the advantageous potential for the safe and efficient treatment of environmental pollutants.