Biochar pyrolyzed from MgAl-layered double hydroxides pre-coated ramie biomass (Boehmeria nivea (L.) Gaud.): Characterization and application for crystal violet removal. (15th December 2016)

• Record Type: Journal Article
• Authors: Tan, Xiao-fei; Liu, Yun-guo; Gu, Yan-ling; Liu, Shao-bo; Zeng, Guang-ming; Cai, Xiaoxi; Hu, Xin-jiang; Wang, Hui; Liu, Si-mian; Jiang, Lu-hua
• Is Part Of: Journal of environmental management. Volume 184:Part 1(2016)
• Page Start: 85
• Page End: 93
• Publication Date: 2016-12-15
• Subjects: Biochar -- MgAl-layered double hydroxides -- Composite -- Ramie (Boehmeria nivea (L.) Gaud.) -- Crystal violet; Environmental policy -- Periodicals; Environmental management -- Periodicals; Environment -- Periodicals; Ecology -- Periodicals; 363.705
• DOI: 10.1016/j.jenvman.2016.08.070
• Languages: English
• ISSNs: 0301-4797

Abstract

Abstract: A novel biochar/MgAl-layered double hydroxides composite (CB-LDH) was prepared for the removal of crystal violet from aqueous solution by pyrolyzing MgAl-LDH pre-coated ramie stem ( Boehmeria nivea (L.) Gaud.). Pyrolysis played dual role for both converting biomass into biochar and calcining MgAl-LDH during the pyrolysis process. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray analysis (EDS), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) and zeta potential analysis were used to characterize the CB-LDH. The results of characterization suggested that the calcined LDH was successfully synthesized and coated on biochar. The resulted CB-LDH had higher total pore volume and more functional groups than the pristine biochar. Adsorption experimental data fitted well with the pseudo-second order kinetics model and the Freundlich isotherm model. The rate-controlled step was controlled by film-diffusion initially and then followed by intra-particle diffusion. Thermodynamic analysis showed that the adsorption of crystal violet was a spontaneous and endothermic process. The higher pH and temperature of the solution enhanced the adsorption performance. CB-LDH could also have excellent ability for the removal of crystal violet from the actual industrial wastewater and groundwater with high ionic strength. LDH adsorption, electrostatic attraction, pore-filling, π–π interaction and hydrogen bond might be the main mechanisms for crystal violet adsorption on CB-LDH. The results of this study indicated that CB-LDH is a sustainable and green adsorbent with high performance for crystal violet contaminated wastewater treatment and groundwater remediation. Graphical abstract: Highlights: Calcined biochar/MgAl-LDH was prepared by pyrolyzing LDH pre-coated ramie stem. Pyrolysis played dual role for both producing biochar and calcining LDH. Calcined LDH was successfully synthesized and coated on biochar. CB-LDH had excellent ability for the removal of crystal violet from aqueous solutions. CB-LDH had high performance for wastewater treatment and groundwater remediation.