Performance and mechanism of Mg-Ca-Fe hydrotalcite-like compounds for fluoride removal from aqueous solution

Ma, Wenqing; Chen, Yuantao; Zhang, Wei; Zhao, Wei

doi:10.1016/j.jfluchem.2017.06.012

Cited by 29 publications

(14 citation statements)

References 49 publications

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“…Contact time is a key parameter by which to assess the performance of the adsorbent, especially in the progress of actual wastewater treatment, where economic benefits are concerned [ 25 ]. The influence when the contact time is raised from 1 to 20 h at 293 K is shown in Figure 5 .…”

Section: Resultsmentioning

confidence: 99%

“…Simulating the experimental data using the Langmuir isotherm model and the Freundlich isotherm model can help us to further understand the mechanism of Cl − removal. The Langmuir isotherm assumes that, based on the monolayer adsorption, the adsorption of adsorbate molecules on the active site is uniform, while the Freundlich isotherm assumes the adsorption is multilayer and heterogeneous; the model is applicable to chemical adsorption [ 25 , 55 ]. The expressions of these models can be respectively presented as follows:

where q e (mg g −1 ) and q m (m mol g −1 ) represent the equilibrium capacity and the maximum adsorption capacity, respectively.…”

Section: Resultsmentioning

confidence: 99%

“…A certain amount of the adsorbent was put into the flasks at 293 K. The mixed solution was stirred magnetically at 300–320 r/min for 2 h. The Cl − concentration of the supernatant was detected using an ion chromatograph (Thermo Fisher Scientific). The removal rate calculation formula is as follows [ 25 ]:

where Y (%) is the Cl − removal rate and C 0 (mg L −1 ) and C e (mg L −1 ) are the initial and equilibrium concentrations of Cl − , respectively.…”

Section: Methodsmentioning

confidence: 99%

“…LDHs, also known as hydrotalcites, are a class of two-dimensional anionic intercalation materials with a bimetallic hydroxide laminate and exchangeable intercalation anions [ 13 ]. They are widely applied in adsorption, catalysis [ 14 , 15 , 16 ], energy storage [ 17 , 18 ], biology [ 19 ], medicine release [ 20 , 21 , 22 ], heavy metal ions [ 23 , 24 ], and functional materials [ 25 , 26 , 27 , 28 ]. Their general formula can be given by (M 2+ 1−x M 3+ x (OH) 2 ) (A n− ) x/n ·mH 2 O [ 29 ].…”

Section: Introductionmentioning

confidence: 99%

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The Performance and Mechanism of a Mg-Al Double-Layer Oxide in Chloride ion Removal from an Aqueous Solution

Yang

et al. 2022

Nanomaterials

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The increasing threat of chloride ions (Cl−) has led researchers to explore efficient removal technologies. Sewage treatment with a double-layer hydroxide/oxide (LDH/LDO) is receiving increasing attention. In this work, Mg-Al LDO adsorbents were produced by the calcination of the Mg-Al LDH precursor, which was constituted by improved coprecipitation. The influence of calcination temperature, calcination time, adsorbent dosage, Cl− initial concentration, contact time, and adsorption temperature on Cl− elimination was investigated systematically. The experimental results showed that a better porous structure endowed the Mg-Al LDO with outstanding adsorption properties for Cl−. The adsorption process was well matched to the pseudo-second-order kinetics model and the Freundlich model. Under optimal conditions, more than 97% of the Cl− could be eliminated. Moreover, the removal efficiency was greater than 90% even after 11 adsorption–desorption cycles. It was found that the electrostatic interaction between Cl− and the positively charged Mg-Al LDO laminate, coupled with the reconstruction of the layer structure, was what dominated the Cl− removal process.

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Section: Resultsmentioning

confidence: 99%

where q e (mg g −1 ) and q m (m mol g −1 ) represent the equilibrium capacity and the maximum adsorption capacity, respectively.…”

Section: Resultsmentioning

confidence: 99%

where Y (%) is the Cl − removal rate and C 0 (mg L −1 ) and C e (mg L −1 ) are the initial and equilibrium concentrations of Cl − , respectively.…”

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The Performance and Mechanism of a Mg-Al Double-Layer Oxide in Chloride ion Removal from an Aqueous Solution

Yang

et al. 2022

Nanomaterials

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“…This phenomenon might be due to the positive surplus charges, which were generated by the formation of an LDH structure (replacing some of the divalent cations by trivalent cations) [ 18 ]. Normally, the anions were first adsorbed on the surface and edge of the adsorbent by electrostatic effects and then exchanged with the interlayer anions of hydrotalcite-like compounds [ 29 ]. As shown in Figure 7 , at low pH (pH < 9), CSLDO400 was always positively charged, which might be helpful for electrostatic interaction.…”

Section: Resultsmentioning

confidence: 99%

Calcined Chitosan-Supported Layered Double Hydroxides: An Efficient and Recyclable Adsorbent for the Removal of Fluoride from an Aqueous Solution

Zhang

Yang

et al. 2017

Materials

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In this work, calcined chitosan-supported layered double hydroxides (CSLDO) were synthesized through a co-precipitation method that restrained the particles’ aggregation of LDHs and exhibited huge specific surface areas, which can enhance the fluoride adsorption capacity. CSLDOs were characterized by physical and chemical methods and used for fluoride adsorption in an aqueous solution. The results indicated that the nanoparticles were constructed first and then assembled to form a porous and layered structure, and chitosan-supported layered double hydroxides (CSLDHs) calcined at 400 °C (CSLDO400) showed the highest specific surface area of 116.98 m2·g−1 and the largest pore volume of 0.411 cm3·g−1. CSLDO400 exhibited excellent adsorption performance at a wide pH range from 5 to 9 for fluoride. The adsorption kinetics indicated that the adsorption reached equilibrium after 120 min, and followed a pseudo-first-order model. It agreed well with the Langmuir isotherm with maximum adsorption amounts of 27.56 mg·g−1. The adsorption of fluoride ions was spontaneous and endothermic. Furthermore, CSLDO400 showed a high stability for fluoride removal; it could still achieve 68% removal for fluoride after repeating five times of adsorption–desorption cycles. This study demonstrated that CSLDO400 is a promising functional material to remove fluoride from surface/ground water.

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Fabricated design of hydrotalcite embedded lanthanum organic frameworks for defluoridation of water

Jeyaseelan

Viswanathan

Govindasamy

et al. 2023

Env Prog and Sustain Energy

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The surplus fluoride in drinking water leads to diseases namely fluorosis (dental, skeletal, and non‐skeletal). Hence, to overcome these problems, in this study, hydrotalcite (HT) integrated La‐based metal‐organic frameworks (LaMOFs) namely HT‐LaMOFs was fabricated for fluoride removal. The fabricated HT‐LaMOFs material was well characterized by various characterization methods (x‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), Energy‐dispersive X‐ray spectroscopy (EDAX), thermogravimetric analysis (TGA), and differential thermal analysis (DTA)) to find the structural properties and stability of HT‐LaMOFs. To find the fluoride adsorption nature, the batch studies were employed towards fluoride adsorption such as reaction time, co‐ions, HT‐LaMOFs dosage, pH, initial fluoride concentration, selectivity, pHzpc, and temperature studies. The contact time studies results reveals that the defluoridation capacity (DC) of HT‐LaMOFs was towards fluoride was found as 4451 mgF− kg−1 at 30 min than HT (1030 mgF− kg−1 at 50 min). The DC had little influences in the presence of HCO3− ion compared to other ions. Fluoride adsorption mechanism of HT‐LaMOFs was initiated to be electrostatic interaction, ion‐exchange and complexation. Fluoride adsorption onto HT‐LaMOFs was well matched and followed with Langmuir model. Thermodynamic investigations exposed that the adsorption of fluoride onto HT‐LaMOFs followed by spontaneous and endothermic nature. Kinetic studies of HT‐LaMOFs on fluoride capture followed with pseudo‐second‐order and intraparticle diffusion models. Defluoridation by HT‐LaMOFs was followed endothermic with spontaneous nature of adsorption system. The regeneration study results of HT‐LaMOFs revealed that the developed HT‐LaMOFs was regenerable up to six cycles. In addition, field study outcomes revealed that the developed HT‐LaMOFs diminished fluoride concentration under the acceptable limit as 1.5 mg/L.

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Performance and mechanism of Mg-Ca-Fe hydrotalcite-like compounds for fluoride removal from aqueous solution

Cited by 29 publications

References 49 publications

The Performance and Mechanism of a Mg-Al Double-Layer Oxide in Chloride ion Removal from an Aqueous Solution

The Performance and Mechanism of a Mg-Al Double-Layer Oxide in Chloride ion Removal from an Aqueous Solution

Calcined Chitosan-Supported Layered Double Hydroxides: An Efficient and Recyclable Adsorbent for the Removal of Fluoride from an Aqueous Solution

Fabricated design of hydrotalcite embedded lanthanum organic frameworks for defluoridation of water

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