Nitrogen-doped carbons from in-situ glucose-coated ZIF-8 as efficient adsorbents for Rhodamine B removal from wastewater

Abstract

The development of new adsorbents for dye-bearing water treatment attracted significant attention. Here, N-doped carbons were obtained by carbonization of partially dehydrated glucose-coated ZIF-8 at 1000 °C via changing glucose mass in hydrothermal system. The structure and removal performance for Rhodamine B (RhB) were studied. The as-made carbon samples exhibited surface areas in the ranges of 850–1200 m2/g and restrained N-species loss from ZIF-8 because of further polymerization outside surface, making them with high N-species and good removal performance. Adsorption kinetics indicated that the sample of GZC-10 exhibited the largest adsorbed amount of 283 mg/g at 25 °C under initial concentration of 300 mg/L as equilibrium time up to 240 min, and pseudo-second order model could be well used to describe diffusion for RhB molecules. Isotherms indicated that Langmuir model expressed a better conformity than Freundlich model with the maximum adsorbed RhB amount of 383 mg/g, much larger than that of other reported MOF-derived carbons. All results indicated that the present carbons were efficient in water treatment considering the satisfactory performance i.e. high adsorption capacity, fast kinetic, and good wettability.