Water-n-BuOH solvothermal synthesis of ZnAl-LDHs with different morphologies and its calcined product in efficient dyes removal.
In this study, water-n-BuOH mixed solvents were used to synthesize the ZnAl-layered double hydroxides (ZnAl-LDHs) via hydrothermal method. The XRD, FT-IR, SEM, ICP and CHN analyses revealed that the type of intercalated anions, the layer Zn/Al ratios, and morphologies of the LDHs depended on the ratio of V(water)/V(n-BuOH) in the mixed solvents. When the ratio of V(water)/V(n-BuOH) is 3 or 0.3, the as-prepared LDHs had 3D "silk flowers" (ZnAl-LDH-3) or "Sedimentary rock" morphology (ZnAl-LDH-0.3). Adsorption properties of dyes on calcined LDHs were studied. Compared with ZnAl-LDO-0.3 and ZnAl-LDO-w (calcined from the LDHs obtained in pure water), ZnAl-LDO-3 showed much better adsorption efficiency for anionic dyes thanks to its much larger BET-specific surface area. The sorption kinetics for dyes was appropriately described by the pseudo-second-order model and sorption isotherms can be fitted more satisfactorily by the Langmuir model. With the increasing concentrations of dyes from 10mg/L to 400mg/L, the maximum absorption capacities of ZnAl-LDO-3 were 1540mg/g (2.21mmol/g) for congo red, 1153mg/g (3.52mmol/g) for methyl orange and 390mg/g (0.63mmol/g) for active red (X-3B), respectively. The adsorption dyes onto the external surface is still the main mechanism for LDO adsorbents. The ZnAl-LDO-3 was a potential adsorbent for dyeing wastewater treatment.
School of Materials and Chemical Engineering, Zhengzhou University of Light Industry, Zhengzhou 450001, China. Electronic address: glhuang99@126.com.
Gailing
G
Huang
School of Materials and Chemical Engineering, Zhengzhou University of Light Industry, Zhengzhou 450001, China.
Yingying
Y
Sun
School of Materials and Chemical Engineering, Zhengzhou University of Light Industry, Zhengzhou 450001, China.
Chencong
C
Zhao
School of Materials and Chemical Engineering, Zhengzhou University of Light Industry, Zhengzhou 450001, China.
Yifei
Y
Zhao
School of Materials and Chemical Engineering, Zhengzhou University of Light Industry, Zhengzhou 450001, China.
Zhaoyuan
Z
Song
School of Materials and Chemical Engineering, Zhengzhou University of Light Industry, Zhengzhou 450001, China.
Junli
J
Chen
Beijing Key Laboratory of Energy Conversion and Storage Materials, College of Chemistry, Beijing Normal University, Beijing 100875, China.
Shulan
S
Ma
School of Materials and Chemical Engineering, Zhengzhou University of Light Industry, Zhengzhou 450001, China; Key Laboratory of Synthetic and Self-Assembly Chemistry for Organic Functional Molecules, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China.
Junping
J
Du
School of Materials and Chemical Engineering, Zhengzhou University of Light Industry, Zhengzhou 450001, China.
Zhigang
Z
Yin
Adsorption mechanism; Layered double hydroxides; Morphologies; Removal of dyes; Water–n-BuOH solvent