Adsorption of methylene blue onto porous carbon material prepared from Na2EDTA
Disodium ethylenediamine tetraacetate (Na2EDTA) is a commonly used reagent in laboratory, which has high oxygen and nitrogen content. In this study, Na2EDTA was employed as precursor to fabricate porous carbon (PC) material through one-step pyrolysis process under different temperature (650 and 750°C). The obtained PC samples was systematically characterized and employed as adsorbent for methylene blue (MB) adsorption by batch experiment. Results showed that the PC samples owned satisfying specific surface area and pore volume through the direct one-step pyrolysis process and higher pyrolysis temperature (750°C) favored the formation of mesopore. The formation of the pore structure can be attributed to the existence of large amount of alkaline functional groups in Na2EDTA, which exhibited a pore-making effect during the pyrolysis process. Adsorption experiments indicated that MB binding onto the PC samples obeyed the pseudo-second-order kinetic model and Langmuir isotherm model. The maximum adsorption capacities calculated from Langmuir model were 734.4 and 1354.7 mg g−1 for PC650 and PC750 respectively, which is comparable or much higher than most of the adsorbent reported recently. Further, the PC sample exhibited extensive adsorption performance for other dyes including cation and anion dyes. In addition, the carbon materials can be regenerated with ethanol and still maintained high adsorption performance even after 4 regeneration cycles, indicating superior recyclability. This study provided a simple one-step pyrolysis method to prepare porous carbon material through self-activation effect.