Adsorption performance of Pb（Ⅱ） by nitrogen-doped mesoporous carbon in tunnel construction wastewater

Nitrogen-doped mesoporous carbon（NMC） was synthesized using hard-template，and was characterized using specific surface area analyzer，transmission electron microscope，Fourier transform-infrared spectrometer and X-ray photoelectron spectroscopy. NMC was applied in the adsorption of Pb（Ⅱ） in two different tunnel construction wastewaters，and the effects of pH，reaction time on adsorption and its adsorption kinetics models and sorption isotherms were investigated. The results showed that the adsorption kinetics was best described by pseudo-second-order model，and its adsorption characteristics conformed to the Langmuir and Temkin model. According to the results of the experiments and characterization，Pb（Ⅱ） adsorption by NMC involved physisorption such as electrostatic interaction and pore diffusion and chemisorption like chelation with functional groups. The estimated maximum adsorption capacity based on Langmuir model was 493.5 mg/g and 603.9 mg/g，respectively for the two wastewaters. In addition，NMC could be regenerated and reused by treatment with HCl.