Carbon-doped graphitic carbon nitride as environment-benign adsorbent for methylene blue adsorption: Kinetics, isotherm and thermodynamics study

A novel, carbon-doped graphitic carbon nitride (C C 3 N 4 -20) was used for methylene blue (MB) removal from an aqueous solution. In dye adsorption experiments, C C 3 N 4 -20 showed a high MB adsorption efficiency due to its extended π-conjugation system and porous structure, the maximum adsorption capacity of C C 3 N 4 -20 for MB was 57.87 mg g −1 , when the initial concentrations of MB were 20 mg L −1 . A Langmuir model fit the MB adsorption isotherm of C C 3 N 4 -20, and a pseudo-second-order kinetic model fit the adsorption kinetics. The MB adsorption process on C C 3 N 4 -20 is physical and mainly via electrostatic attraction and π–π interactions.