Halloysite and coconut shell biochar magnetic composites for the sorption of Pb(II) in wastewater: Synthesis, characterization and mechanism investigation. Issue 6 (December 2021)

• Record Type: Journal Article
• Authors: Wang, Shenwan; Xiao, Dao; Zheng, Xiaoyan; Zheng, Lili; Yang, Yang; Zhang, Haide; Ai, Binling; Sheng, Zhanwu
• Is Part Of: Journal of environmental chemical engineering. Volume 9:Issue 6(2021)
• Publication Date: 2021-12
• Subjects: BC Biochar -- HNTs Halloysite nanotubes -- SEM scanning electron microscopy -- BET Brunauer–Emmett–Teller -- BJH Barrett–Joyner–Halenda -- FTIR Fourier transform infrared -- XRD X-ray diffractometry -- XPS X-ray photoelectron spectroscopy -- CS coconut shells; Biochar -- Halloysite -- Magnetic adsorbents -- Ball mill -- Pb(II); Chemical engineering -- Environmental aspects -- Periodicals; Environmental engineering -- Periodicals; Chemical engineering -- Environmental aspects; Environmental engineering; Periodicals; 660.0286
• DOI: 10.1016/j.jece.2021.106865
• Languages: English
• ISSNs: 2213-2929

Abstract

Abstract: Halloysite/biochar was prepared by co-pyrolysis at different temperatures using coconut shell and halloysite as raw materials. Magnetic adsorbents were prepared through ball-mill extrusion with Fe3 O4 and the halloysite/biochar and the capacity of the adsorbents to adsorb Pb(II) from water was evaluated and compared. The effects of pH, contact time, and initial Pb(II) concentration on the adsorption capacity of the magnetic adsorbents for Pb(II) were investigated. The pseudo-second-order ( R 2 =0.9999) and Langmuir isothermal models ( R 2 =0.9906) fit the experimental data well. The prepared samples denotes as MBM-HBC700 exhibited the highest Pb(II) adsorption capacity (833.33 ± 16.71 mg·g -1 ), and the removal efficiency of Pb(II) by the magnetic adsorbents was above 90% after four adsorption–desorption cycles. Complexation, cation exchange, cation–π interaction, precipitation, pore filling and electrostatic adsorption have been proposed as the main removal mechanisms. After applying MBM-HBCs to simulated electroplating wastewater, the contents of Pb(II), Cu(II), Zn(II), and Cr(VI) were significantly lower than the discharge standard of China. The magnetic adsorbents prepared in this study have wide application prospects in the treatment of Pb(II) in wastewater, thus providing a new approach for promoting waste recycling and utilization. Graphical Abstract: ga1 Highlights: ● Magnetic halloysite/biochar were prepared through ball-mill extrusion with Fe3 O4 ● The modified biochar exhibited extraordinary Pb(II) adsorption capacity ● Remained great Pb(II) removal efficiency after four adsorption–desorption cycles ● Adsorption mechanisms: complexation, cation exchange, cation–π interaction, etc. ● Removed Pb(II), Cu(II), Zn(II), and Cr(VI) from simulated electroplating wastewater