title: Superior adsorption capacity of g-C₃N₄ for heavy metal ions from aqueous solutions.
abstract: In this work, graphitic-C3N4 (g-C3N4) was synthesized by a simple and environmentally friendly salt melt method, and characterized by using field-emission scanning and transmission electron microscopy, X-ray diffraction, Fourier transformed infrared spectroscopy, X-ray photoelectron spectroscopy and N2 adsorption-desorption analysis. The as-prepared g-C3N4 was used as an adsorbent to remove heavy metal ions from aqueous solutions. The adsorption kinetics of Pb(II) and Cu(II) followed the pseudo-second-order model. The g-C3N4 exhibited much higher adsorption capacity toward heavy metal ions (1.36 mmol/g for Pb(II), 2.09 mmol/g for Cu(II), 1.00 mmol/g for Cd(II) and 0.64 mmol/g for Ni(II)) than other adsorbents. The adsorption of Pb(II) and Cu(II) on g-C3N4 was slightly affected by ionic strength at pH<5.0 and increased with the increase of ionic strength at pH>5.0. The inner-sphere surface complexation mechanism was suitable to explain the interaction between heavy metal ions and the nitrogen- and carbon-containing functional groups of the g-C3N4. The experimental results reveal that g-C3N4 is a potential adsorbent for the removal of heavy metal ions from large volumes of aqueous solutions.
authors.affiliation: College of Nuclear Science and Technology, University of Science and Technology of China, Hefei 230026, PR China.
authors.forename: Congcong
authors.initials: C
authors.lastname: Shen
authors.affiliation: Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, 230031 Hefei, PR China. Electronic address: clchen@ipp.ac.cn.
authors.forename: Changlun
authors.initials: C
authors.lastname: Chen
authors.affiliation: Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, 230031 Hefei, PR China.
authors.forename: Tao
authors.initials: T
authors.lastname: Wen
authors.affiliation: College of Nuclear Science and Technology, University of Science and Technology of China, Hefei 230026, PR China.
authors.forename: Zhiwei
authors.initials: Z
authors.lastname: Zhao
authors.affiliation: Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, 230031 Hefei, PR China; Faculty of Engineering, King Abdulaziz University, Jeddah 21589, Saudi Arabia.
authors.forename: Xiangke
authors.initials: X
authors.lastname: Wang
authors.affiliation: Division of Nanomaterials and Chemistry, Hefei National Laboratory for Physical Sciences at Microscale Department, University of Science and Technology of China, Hefei 230026, PR China. Electronic address: anwuxu@ustc.edu.cn.
authors.forename: Anwu
authors.initials: A
authors.lastname: Xu
keywords: Adsorption; Graphitic-C(3)N(4); Heavy metal ions