title: Superb adsorption capacity of hierarchical calcined Ni/Mg/Al layered double hydroxides for Congo red and Cr(VI) ions.
abstract: The preparation of hierarchical porous materials as catalysts and sorbents has attracted much attention in the field of environmental pollution control. Herein, Ni/Mg/Al layered double hydroxides (NMA-LDHs) hierarchical flower-like hollow microspheres were synthesized by a hydrothermal method. After the NMA-LDHs was calcined at 600°C, NMA-LDHs transformed into Ni/Mg/Al layered double oxides (NMA-LDOs), which maintained the hierarchical flower-like hollow structure. The crystal phase, morphology, and microstructure of the as-prepared samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy elemental mapping, Fourier transform infrared spectroscopy, and nitrogen adsorption-desorption methods. Both the calcined and non-calcined NMA-LDHs were examined for their performance to remove Congo red (CR) and hexavalent chromium (Cr(VI)) ions in aqueous solution. The maximum monolayer adsorption capacities of CR and Cr(VI) ions over the NMA-LDOs sample were 1250 and 103.4mg/g at 30°C, respectively. Thermodynamic studies indicated that the adsorption process was endothermic in nature. In addition, the addition of coexisting anions negatively influenced the adsorption capacity of Cr(VI) ions, in the following order: CO32->SO42->H2PO4->Cl-. This work will provide new insight into the design and fabrication of advanced adsorption materials for water pollutant removal.
authors.affiliation: State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, PR China; College of Environmental & Safety Engineering, Changzhou University, Changzhou 213164, PR China.
authors.forename: Chunsheng
authors.initials: C
authors.lastname: Lei
authors.affiliation: College of Environmental & Safety Engineering, Changzhou University, Changzhou 213164, PR China.
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Zhu
authors.affiliation: State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, PR China.
authors.forename: Bicheng
authors.initials: B
authors.lastname: Zhu
authors.affiliation: State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, PR China.
authors.forename: Chuanjia
authors.initials: C
authors.lastname: Jiang
authors.affiliation: State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, PR China.
authors.forename: Yao
authors.initials: Y
authors.lastname: Le
authors.affiliation: State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, PR China; Department of Physics, Faculty of Science, King Abdulaziz University, Jeddah 21589, Saudi Arabia. Electronic address: jiaguoyu@yahoo.com.
authors.forename: Jiaguo
authors.initials: J
authors.lastname: Yu
keywords: Adsorption; Congo red; Cr(VI) ion; Hierarchical hollow sphere; Layered double hydroxide