Adsorption Removal of Pollutant Dyes in Wastewater by Nitrogen-doped Porous Carbons Derived from Natural Leaves

Jun Chen1 

Xiaosu Wang1 

Yan Huang1,Email 

Shanshan Lv1,Email 

Xiaohua Cao3 

Jimmy Yun4

Dapeng Cao1,2,3,Email

1 State Key Laboratory of Organic-Inorganic Composite Materials, Beijing University of Chemical Technology, Beijing, 100029, China

2 Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing, 100029, China

3 College of Chemical and Environmental Engineering, Jiujiang University, Jiujiang, Jiangxi, 332005, China

4 School of Chemical Science and Engineering, The University of New South Wales, Sydney, NSW2052, Australia

Abstract

An easy pyrolysis and activation synthesis method has been proposed to convert a common biomass waste of Euonymus japonicus leaves into nitrogen-doped porous carbons (NPCs), and its application in the removal of methylene blue (MB), methylene orange (MO) and rhodamine B (RhB) from simulated wastewater was further explored. The uptake of NPCs for dyes increases along with the initial dye concentration and contact time but decreases with the NPC dosage. The adsorption capacities of the NPCs for MB, RhB and MO were 626.1, 620.7 and 370.8 mg·g-1, respectively, which meant that the NPCs were better adsorbents for cationic dyes (MB and RhB), compared to the anionic dye (MO), because the NPC surfaces carry partial negative charges. In order to elaborate the adsorption mechanism, the kinetics data were analyzed by pseudo-first order, pseudo-second order, intra-particle diffusion and Elovich models, in which the pseudo-second order model exhibited the best fit. The adsorption data were evaluated by Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherm models, in which the Langmuir model could well describe the adsorption processes. This study presented a potential alternative low-cost high efficient adsorbent for removing pollutant dyes from wastewater through using biomass waste leaves as sources.