Adsorption of Cr(VI) from aqueous solution on mesoporous carbon nitride

Mesoporous carbon nitride (MCN) was synthesized using mesoporous silica SBA-15 as the template and employed for the adsorption of Cr(VI) from aqueous solutions. Cr(VI) adsorption over MCN followed pseudo-second-order kinetic model and the Langmuir adsorption model. The maximum sorption capacity of MCN for Cr(VI) was 48.31 mg/g at pH 5.7, higher than activated carbon (AC) and ordered mesoporous carbon (CMK-3). An electrostatic interaction mechanism between Cr(VI) and surface pyridine groups on MCN was proposed by Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) analysis. The coexisting anions, especially the carbonate, influenced the adsorption amount due to the competitive adsorption of Cr(VI) on the surface of MCN. The adsorbed Cr(VI) could be effectively desorbed by 0.5 mol/L NaOH solution, suggesting that MCN could be a promising adsorbent for Cr(VI) removal from waste effluents. (C) 2014 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

以介孔二氧化硅SBA - 15为模板合成了介孔氮化碳（MCN），并将其用于水溶液中Cr(VI)的吸附。MCN对Cr(VI)的吸附符合准二级动力学模型和朗缪尔吸附模型。在pH为5.7时，MCN对Cr(VI)的最大吸附量为48.31 mg/g，高于活性炭（AC）和有序介孔碳（CMK - 3）。通过傅里叶变换红外光谱（FT - IR）和X射线光电子能谱（XPS）分析，提出了Cr(VI)与MCN表面吡啶基团之间的静电相互作用机制。共存阴离子，尤其是碳酸根，由于Cr(VI)在MCN表面的竞争吸附而影响了吸附量。吸附的Cr(VI)可以用0.5 mol/L的NaOH溶液有效解吸，这表明MCN可能是一种用于去除废水中Cr(VI)的有前景的吸附剂。（C）2014台湾化学工程师学会。由爱思唯尔出版有限公司出版。保留所有权利。