title: Enhanced Adsorption of Hydroxyl- and Amino-Substituted Aromatic Chemicals to Nitrogen-Doped Multiwall Carbon Nanotubes: A Combined Batch and Theoretical Calculation Study.
abstract: A large effort is being made to develop nanosorbents with tunable surface chemistry for enhanced adsorption affinity and selectivity toward target organic contaminants. Heteroatom N-doped multiwall carbon nanotubes (N-MCNT) were synthesized by chemical vapor deposition of pyridine and were further investigated for the adsorptive removal of several aromatic chemicals varying in electronic donor and acceptor ability from aqueous solutions using a batch technique. Compared with commercial nondoped multiwall carbon nanotubes (MCNT), N-MCNT had similar specific surface area, morphology, and pore-size distribution but more hydrophilic surfaces and more surface defects due to the doping of graphitic and pyridinic N atoms. N-MCNT exhibited enhanced adsorption (2-10 folds) for the π-donor chemicals (2-naphthol and 1-naphthalmine) at pH ∼6 but similar adsorption for the weak π-donor chemical (naphthalene) and even lower adsorption (up to a 2-fold change) for the π-acceptor chemical (1,3-dinitrobenzene). The enhanced adsorption of 2-naphthol and 1-naphthalmine to N-MCNT was mainly attributed to the favored π-π electron-donor-acceptor (EDA) interaction between the π-donor adsorbate molecule and the polarized N-heterocyclic aromatic ring (π-acceptor) on N-MCNT. The proposed adsorption enhancement mechanisms were further tested through the pH effects on adsorption and the density function theory (DFT) calculation. The results show for the first time that the adsorptive interaction of π-donor aromatic compounds with carbon nanomaterials can be facilitated by N-doping.
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse and School of the Environment, Nanjing University , Nanjing, Jiangsu 210093, China.
authors.forename: Linzi
authors.initials: L
authors.lastname: Zuo
authors.affiliation: Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University , Nanjing, Jiangsu 210090, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Guo
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse and School of the Environment, Nanjing University , Nanjing, Jiangsu 210093, China.
authors.forename: Xiao
authors.initials: X
authors.lastname: Li
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse and School of the Environment, Nanjing University , Nanjing, Jiangsu 210093, China.
authors.forename: Heyun
authors.initials: H
authors.lastname: Fu
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse and School of the Environment, Nanjing University , Nanjing, Jiangsu 210093, China.
authors.forename: Xiaolei
authors.initials: X
authors.lastname: Qu
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse and School of the Environment, Nanjing University , Nanjing, Jiangsu 210093, China.
authors.forename: Shourong
authors.initials: S
authors.lastname: Zheng
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse and School of the Environment, Nanjing University , Nanjing, Jiangsu 210093, China.
authors.forename: Cheng
authors.initials: C
authors.lastname: Gu
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse and School of the Environment, Nanjing University , Nanjing, Jiangsu 210093, China.|School of Urban and Environmental Sciences, Peking University , Beijing 100871, China.
authors.forename: Dongqiang
authors.initials: D
authors.lastname: Zhu
authors.affiliation: Department of Civil and Environmental Engineering, Rice University , Houston Texas 77005, United States.
authors.forename: Pedro J J
authors.initials: PJ
authors.lastname: Alvarez
mesh_terms: D000327:Adsorption; D006841:Hydrocarbons, Aromatic / Q000737:chemistry*; D017665:Hydroxyl Radical; D037742:Nanotubes, Carbon / Q000737:chemistry*; D009584:Nitrogen / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry
chemical_list: D006841:Hydrocarbons, Aromatic; D037742:Nanotubes, Carbon; D014874:Water Pollutants, Chemical; D017665:Hydroxyl Radical; D009584:Nitrogen