Chitosan modified nitrogen-doped porous carbon composite as a highly-efficient adsorbent for phenolic pollutants removal

In this work, a chitosan modified nitrogen-doped porous carbon composite (CS-NPC) with abundant micropore and mesopore was prepared by the hydrothermal carbonization combined with chemical activation, and used as an adsorbent for phenolic pollutants removal. The CS-NPC composite were characterized by the field emission scanning electron microscopy (FE-SEM), N-2 adsorption-desorption curves, X-ray photoelectron spectrum (XPS), X-ray diffraction (XRD) and Raman. It was found that the resulting carbon material owned large specific surface areas (2189.88 m(2) g(-1)) and total pore volume (1.123 cm(3) g(-1)), and its micropore and mesopore volume was 0.494 and 0.629 cm(3)g(-1), respectively. Batch adsorption experiments were carried out to study the impact of various factors like solution pH value, contact time and ionic intensity. The adsorption process can be described by the pseudo-second-order kinetic model and Langmuir adsorption isotherm model. And at 298 K, the adsorption capability of the CS-NPC composite for phenol, BPA and 2,4-DCP was 254.45, 675.68 and 892.86 mg g(-1), respectively, which was much higher than that of previously reported carbon-based materials due to its own high specific surface areas, abundant functional groups (-NH2 , -OH) and porous structure. The adsorbent still remained excellent regeneration after five cycles. And the CS-NPC composite can be regarded as a broadspectrum adsorbent toward other organic pollutants including methyl orange, methylene blue and tetracycline. This study developed a novel, low-cost and green porous carbon composite which was combined with the advantage of both phenolic resin and CS, and the CS-NPC would be an outstanding adsorbent for the removal of various organic contaminants from wastewater.

Automated summary

A chitosan modified nitrogen-doped porous carbon composite (CS-NPC) with abundant micropore and mesopore was prepared for phenolic pollutants removal. The composite exhibited a high specific surface area and pore volume, excellent adsorption capacity for phenol, BPA and 2,4-DCP, and good regeneration performance after multiple cycles.