Preparation and evaluation of the Ca-Al layered double hydroxide for removal of copper(II), nickel(II), zinc(II), chromium(VI) and phosphate from aqueous solutions

Milagres, Jaderson L.; Bellato, Carlos Roberto; Vieira, Rogério Sugaki; Ferreira, S. O.; Reis, César

doi:10.1016/j.jece.2017.10.013

Cited by 59 publications

(28 citation statements)

References 46 publications

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“…), and anions (CO 3 2− , SO 4 2− , NO 3 − , Cl − , OH − , etc.) [ 3 , 5 , 6 , 7 , 8 , 9 , 10 ]. Generally, CaAl-Cl-LDHs can effectively absorb “target ions” from an aqueous medium in the following ways: co-precipitation, isomorphic substitution, and surface complexation and chelation [ 11 ].…”

Section: Introductionmentioning

confidence: 99%

Crystalline/Amorphous Blend Identification from Cobalt Adsorption by Layered Double Hydroxides

et al. 2018

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In this study, the adsorption behavior of CaAl-Cl layered double hydroxide (CaAl-Cl-LDH) with a controlled pH value (pH = 6) on Co(II) ions ([Co] = 8 mM) is investigated. The comprehensively accepted mechanism of cobalt adsorption on LDH is considered to be co-precipitation, and the final adsorbed products are normally crystalline Co-LDH. One unanticipated finding is that crystalline/amorphous blends are found in the X-ray diffraction (XRD) pattern of Co-adsorbed LDH. To shed light on the adsorption products and the mechanisms in the adsorption process of Co(II) in an aqueous solution by CaAl-Cl-LDH, a series of testing methods including Fourier-transform infrared spectroscopy (FT-IR), Scanning electron microscope (SEM), High-resolution transmission electron microscopy (HR-TEM), X-ray photoelectron spectroscopy (XPS), and inductively coupled plasma (ICP) are applied to clarify the interaction between cobalt and CaAl-Cl-LDH. According to the comprehensive analysis, the formation of the crystalline/amorphous blends corresponds to two adsorption mechanisms. The crystalline phases are identified as Co6Al2CO3(OH)16·4H2O, which is attributed to the co-precipitation process occurring in the interaction between Co(II) and CaAl-Cl-LDH. The formation of the amorphous phases is due to surface complexation on amorphous Al(OH)3 hydrolyzed from CaAl-Cl-LDH.

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Section: Introductionmentioning

confidence: 99%

Crystalline/Amorphous Blend Identification from Cobalt Adsorption by Layered Double Hydroxides

et al. 2018

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“…As reference material, Cl − -intercalated Mg-Al LDH (pristine LDH) was prepared by the co-precipitation method adapted from [23]. Briefly, 150 mL of an aqueous solution of NaOH (35 mmol) and NaCl (34 mmol) was slowly titrated with an ethanol-water solution of MgCl 2 ·6H 2 O and AlCl 3 ·9H 2 O (Mg/Al molar ratio of 2/1, cations concentration 0.375 mol/L) at 80 °C under nitrogen atmosphere.…”

Section: Methodsmentioning

confidence: 99%

Ionic Liquids as Delaminating Agents of Layered Double Hydroxide during In-Situ Synthesis of Poly (Butylene Adipate-co-Terephthalate) Nanocomposites

et al. 2019

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Currently, highly demanded biodegradable or bio-sourced plastics exhibit inherent drawbacks due to their limited processability and end-use properties (barrier, mechanical, etc.). To overcome all of these shortcomings, the incorporation of lamellar inorganic particles, such as layered double hydroxides (LDH) seems to be appropriate. However, LDH delamination and homogenous dispersion in a polymer matrix without use of harmful solvents, remains a challenging issue, which explains why LDH-based polymer nanocomposites have not been scaled-up yet. In this work, LDH with intercalated ionic liquid (IL) anions were synthesized by a direct co-precipitation method in the presence of phosphonium IL and subsequently used as functional nanofillers for in-situ preparation of poly (butylene adipate-co-terephthalate) (PBAT) nanocomposites. The intercalated IL-anions promoted LDH swelling in monomers and LDH delamination during the course of in-situ polycondensation, which led to the production of PBAT/LDH nanocomposites with intercalated and exfoliated morphology containing well-dispersed LDH nanoplatelets. The prepared nanocomposite films showed improved water vapor permeability and mechanical properties and slightly increased crystallization degree and therefore can be considered excellent candidates for food packaging applications.

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“…Two surface hydroxyl groups are coordinated by each metal cation forming a positively charged sheet. In order to compensate for the positive charge of the layers, exchangeable anions (A n − , e.g., CO 3 2− , NO 3 − , Cl − ) and molecules of water are intercalated into LDH galleries [ 6 , 7 ]. Contrary to natural clays like montmorillonite and kaolinite, the use of LDH in polymer nanocomposites is particularly advantageous because of variable and tunable LDH structure.…”

Section: Introductionmentioning

confidence: 99%

Effects of Immobilized Ionic Liquid on Properties of Biodegradable Polycaprolactone/LDH Nanocomposites Prepared by In Situ Polymerization and Melt-Blending Techniques

2020

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The high capacity of calcinated layered double hydroxides (LDH) to immobilize various active molecules together with their inherent gas/vapor impermeability make these nanoparticles highly promising to be applied as nanofillers for biodegradable polyester packaging. Herein, trihexyl(tetradecyl)phosphonium decanoate ionic liquid (IL) was immobilized on the surface of calcinated LDH. Thus, the synthesized nanoparticles were used for the preparation of polycaprolactone (PCL)/LDH nanocomposites. Two different methods of nanocomposite preparation were used and compared: microwave-assisted in situ ring opening polymerization (ROP) of ε-caprolactone (εCL) and melt-blending. The in situ ROP of εCL in the presence of LDH nanoparticles with the immobilized IL led to homogenous nanofiller dispersion in the PCL matrix promoting formation of large PCL crystallites, which resulted in the improved mechanical, thermal and gas/water vapor barrier properties of the final nanocomposite. The surface-bonded IL thus acted as nanofiller surfactant, compatibilizer, as well as thermal stabilizer of the PCL/LDH nanocomposites. Contrary to that, the melt-blending caused a partial degradation of the immobilized IL and led to the production of PCL nanocomposites with a heterogenous nanofiller dispersion having inferior mechanical and gas/water vapor barrier properties.

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Preparation and evaluation of the Ca-Al layered double hydroxide for removal of copper(II), nickel(II), zinc(II), chromium(VI) and phosphate from aqueous solutions

Cited by 59 publications

References 46 publications

Crystalline/Amorphous Blend Identification from Cobalt Adsorption by Layered Double Hydroxides

Crystalline/Amorphous Blend Identification from Cobalt Adsorption by Layered Double Hydroxides

Ionic Liquids as Delaminating Agents of Layered Double Hydroxide during In-Situ Synthesis of Poly (Butylene Adipate-co-Terephthalate) Nanocomposites

Effects of Immobilized Ionic Liquid on Properties of Biodegradable Polycaprolactone/LDH Nanocomposites Prepared by In Situ Polymerization and Melt-Blending Techniques

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