An azine-based polymer derived hierarchically porous N-doped carbon for hydrophilic dyes removal

In this study, a novel hierarchically porous N-doped carbon (HPNC) material was successfully prepared by soft-templating method. The commercial triblock copolymer of Pluronic F127 and a polyazine derived from hydrazine hydrate & glyoxal were used as soft template and precursor, respectively. The obtained materials were fully characterized and tested as a sorbent for the removal of hydrophilic dyes of Methylene blue (MB), Basic Fuchsin (BF), Eosin Y (EY) and Rhodamine B (RB) from their aqueous effluents. According to the characterization results, the synthesized material of HPNC-1000 presented thick fibrous morphology with micron size in diameter, hierarchically porous structure with surface area of 1853 m²/g, pore volume of 1.59 cm³/g and nitrogen content of 4.5 wt%. Adsorption-desorption investigation reveals that synergistic effect of hydrophobic interaction and hydrogen-bonding formation of the dye molecules with the sorbent was most pronounced in the adsorptions. The maximum adsorption capacities for MB, BF, EY and RB reached 0.83, 0.92, 1.23 and 1.83 mmol g^-1, respectively. The adsorption processes well fitted by the pseudo first-order kinetic model and the Liu's isotherm. The sorbent can be regenerated by above 90% of the initial adsorption efficiency after six regeneration cycles.