title: Adsorption of phosphate from aqueous solution using iron-zirconium modified activated carbon nanofiber: Performance and mechanism.
abstract: Phosphate (P) removal is significant for the prevention of eutrophication in natural waters. In this paper, a novel adsorbent for the removal of P from aqueous solution was synthesized by loading zirconium oxide and iron oxide onto activated carbon nanofiber (ACF-ZrFe) simultaneously. The adsorbent was characterized by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The results showed that P adsorption was highly pH dependent and the optimum pH was found to be 4.0. The isotherm of adsorption could be well described by the Langmuir model and the maximum P adsorption capacity was estimated to be 26.3mgP/g at 25°C. The kinetic data were well fitted to the pseudo-second-order equation, indicating that chemical sorption was the rate-limiting step. Moreover, co-existing ions including sulfate (SO42-), chloride (Cl-), nitrate (NO3-) and fluoride (F-) exhibited a distinct effect on P adsorption with the order of F->NO3->Cl->SO42-. Further investigations by FT-IR spectroscopy and pH variations associated with the adsorption process revealed that ligands exchange and electrostatic interactions were the dominant mechanisms for P adsorption. The findings reported in this work highlight the potential of using ACF-ZrFe as an effective adsorbent for the removal of P in natural waters.
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Ministry of Education, Hunan University, Changsha 410082, China.
authors.forename: Weiping
authors.initials: W
authors.lastname: Xiong
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Ministry of Education, Hunan University, Changsha 410082, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Tong
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Ministry of Education, Hunan University, Changsha 410082, China. Electronic address: yzh@hnu.edu.cn.
authors.forename: Zhaohui
authors.initials: Z
authors.lastname: Yang
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Ministry of Education, Hunan University, Changsha 410082, China. Electronic address: zgming@hnu.edu.cn.
authors.forename: Guangming
authors.initials: G
authors.lastname: Zeng
authors.affiliation: College of Resources and Environment, Hunan Agricultural University, Changsha 410128, China.
authors.forename: Yaoyu
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Ministry of Education, Hunan University, Changsha 410082, China.
authors.forename: Dongbo
authors.initials: D
authors.lastname: Wang
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Ministry of Education, Hunan University, Changsha 410082, China.
authors.forename: Peipei
authors.initials: P
authors.lastname: Song
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Ministry of Education, Hunan University, Changsha 410082, China.
authors.forename: Rui
authors.initials: R
authors.lastname: Xu
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Ministry of Education, Hunan University, Changsha 410082, China.
authors.forename: Chen
authors.initials: C
authors.lastname: Zhang
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Ministry of Education, Hunan University, Changsha 410082, China.
authors.forename: Min
authors.initials: M
authors.lastname: Cheng
mesh_terms: D000327:Adsorption; D007501:Iron / Q000737:chemistry*; D007700:Kinetics; D057139:Nanofibers / Q000737:chemistry*; D010710:Phosphates / Q000737:chemistry* / Q000302:isolation & purification*; D014867:Water / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000302:isolation & purification; D015040:Zirconium / Q000737:chemistry*
chemical_list: D010710:Phosphates; D014874:Water Pollutants, Chemical; D014867:Water; D015040:Zirconium; D007501:Iron
keywords: Activated carbon nanofiber; Adsorption; Iron; Phosphate; Zirconium