title: Biochar pyrolyzed from MgAl-layered double hydroxides pre-coated ramie biomass (Boehmeria nivea (L.) Gaud.): Characterization and application for crystal violet removal.
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.
authors: College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China.
authors: Xiao-Fei
authors: XF
authors: Tan
authors: College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China. Electronic address: hnuliuyunguo@gmail.com.
authors: Yun-Guo
authors: YG
authors: Liu
authors: College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China.
authors: Yan-Ling
authors: YL
authors: Gu
authors: School of Metallurgy and Environment, Central South University, Changsha 410083, PR China; School of Architecture and Art, Central South University, Changsha 410083, PR China.
authors: Shao-Bo
authors: SB
authors: Liu
authors: College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China.
authors: Guang-Ming
authors: GM
authors: Zeng
authors: College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China.
authors: Xiaoxi
authors: X
authors: Cai
authors: College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China; College of Environmental Science and Engineering Research, Central South University of Forestry and Technology, Changsha 410004, PR China.
authors: Xin-Jiang
authors: XJ
authors: Hu
authors: College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China.
authors: Hui
authors: H
authors: Wang
authors: College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China.
authors: Si-Mian
authors: SM
authors: Liu
authors: College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China.
authors: Lu-Hua
authors: LH
authors: Jiang
mesh_terms: D000327:Adsorption; D000536:Aluminum Hydroxide / Q000737:chemistry; D018533:Biomass; D032402:Boehmeria / Q000737:chemistry*; D002606:Charcoal / Q000737:chemistry*; D005840:Gentian Violet / Q000302:isolation & purification*; D060587:Groundwater / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008276:Magnesium Hydroxide / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D056951:Photoelectron Spectroscopy; D012996:Solutions; D013696:Temperature; D013816:Thermodynamics; D062065:Wastewater / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*; D018508:Water Purification / Q000379:methods*
chemical_list: D000536:Aluminum Hydroxide; D002606:Charcoal; D005840:Gentian Violet; D008276:Magnesium Hydroxide; D012996:Solutions; D062065:Wastewater; D014874:Water Pollutants, Chemical; C540010:biochar
keywords: Biochar; Composite; Crystal violet; MgAl-layered double hydroxides; Ramie (Boehmeria nivea (L.) Gaud.)