Water–n-BuOH solvothermal synthesis of ZnAl–LDHs with different morphologies and its calcined product in efficient dyes removal

Abstract

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.

A detailed investigation of MnO2 nanorods to be grown onto activated carbon. High efficiency towards aqueous methyl orange adsorption/degradation

“…A variety of research studies have been recently carried out in order to remove/degrade MO from wastewaters [10][11][12][13][14]. Many technologies, such as chemical oxidation [15], photochemical/ ultrasonic degradation [16,17], reverse osmosis [18] and flotation [19] have been exploited.…”

Amine Resin by Chromium (III)‐Fibrous Protein for Enhanced Removal of Two Reactive Anionic Dyes

“…It took about 7 h for 100 mg/L K-2BP and 9 h for 200 mg/L K-2BP to attain equilibrium, possibly due to the difficulty of adsorbing larger K-2BP molecules for ACrFP. Figure 8 illustrated the effects of different temperatures (20,35, and 50 C) on the adsorption of X-3B and K-2BP on ACrFP resin. Both of the adsorption capacity of ACrFP resin for March 2019 S199 X-3B and K-2BP decreased with an increasing temperature, suggesting the anionic dye sorption on ACrFP resin was favorable at a lower temperature.…”

Renewable metal–organic-frameworks-coated 3D printing film for removal of malachite green

“…S3c and d †), suggesting successful growth of Cu-MOFs on PLA by the in situ stepwise process. The Cu-MOFs/PLA lms with various numbers of layers of MOFs coating (2,4,6,8) are shown in Fig. 2.…”

“…Organic compounds, such as dyes, have been widely used in the dyestuff and pigment industry as well as the food and textile industries. [1][2][3][4][5][6] Although dyes play important roles in our daily life, the discharge of large quantities of these toxic organic compounds into the environment causes considerable pollution, and even serious health issues. [7][8][9][10] For example, malachite green (MG) has been widely used in sh breeding and the textile industry; however, the discharge of MG into water causes toxicity to living organisms.…”