Preparation and characterization of Mg–Al hydrotalcite-like compounds containing cerium

Das, J.; Das, D.P.; Parida, Kulamani

doi:10.1016/j.jcis.2006.05.014

Cited by 83 publications

(41 citation statements)

References 22 publications

(22 reference statements)

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“…As Figure 6 (a -c) depict, the maximum adsorption capacity by CLDH and LDH decreased with increasing initial dye concentration as the number of moles of dye competing for the available surface area of the adsorbent which was fixed for a constant adsorbent dose, increased [16]. The most significant observation in this experiment was the enhanced dye uptake, both in terms of percentage dye removal and adsorption capacity by CLDH over its precursor LDH for any given initial dye concentration.…”

Section: Effect Of Contact Time and Initial Dye Concentrationsmentioning

confidence: 61%

“…The time curves of dye removal for concentrations 50 -100 mg/L in Figure 6 (a -c) are smooth and continuous indicating the possibility of a monolayer formation on adsorbent surface [16] [23]. As Figure 6 (a -c) depict, the maximum adsorption capacity by CLDH and LDH decreased with increasing initial dye concentration as the number of moles of dye competing for the available surface area of the adsorbent which was fixed for a constant adsorbent dose, increased [16].…”

Section: Effect Of Contact Time and Initial Dye Concentrationsmentioning

confidence: 94%

“…Since AC is commercially costly for large scale production and difficult to regenerate, alternative adsorbents are being sought. A positively charged anionic clay known as layered double hydroxide (LDH), with an empirical formula [M Calcination of LDHs at temperature 400 -700 °C can decompose LDH containing carbonate or nitrate to release CO 2 or NO x gas with end products containing a solid mixture of Mg-Al oxide, which can revert to the original structure (reconstruction) of LDH upon rehydration [1,6]. This phenomenon, well known as 'memory effect' was responsible for enhanced uptake of anionic dye removal by CLDH in comparison to its precursor LDH.…”

Section: Introductionmentioning

confidence: 99%

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ADSORPTION OF ANIONIC DYES FROM AQUEOUS SOLUTIONS BY CALCINED AND UNCALCINED Mg/Al LAYERED DOUBLE HYDROXIDE

Sumari

Hamzah

Kantasamy

2016

MJAS

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The uptake of Acid Blue 29 (AB29), Reactive Orange 16 (RO16) and Reactive Red 120 (RR120) from aqueous solutions by calcined (CLDH) and uncalcined Mg/Al layered double hydroxide (LDH) has been investigated. The adsorption process was conducted in a batch mode at 25 °C. Anionic dye removal was more efficient using the CLDH rather than LDH. The adsorption process by CLDH involved reconstruction and hydration of the calcined LDH and intercalation of AB29, RO16 and RR120. Physical characterization using X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Fourier Transform Infrared (FTIR) were used to ascertain the 'memory effect' phenomenon that is structural reconstruction to regain its original LDH after rehydration. To gain insight into the mechanism of adsorption by CLDH, the pseudo-first order (PFO) and pseudo-second order (PSO) and intraparticle diffusion (IPD) kinetic models were used to analyse experimental data. Based on the correlation coefficient (R 2 ), the PSO has better fitting (R 2 = 0.987 -1.00) compared to PFO (R 2 = 0.867 -0.990). Furthermore the values of maximum adsorption capacity, (q e ) calculated from PSO model are consistent with the experimental q e indicating that the experimental kinetic data for AB29, RO16 and RR120 adsorption by CLDH are suitable for this model. Recycling of the adsorbent, in cycles of calcination-reconstruction process promised a possibility of regeneration of CLDH.Keywords: calcined, adsorption capacity, reconstruction, memory effect, regeneration Abstrak Penyingkiran pewarna Acid Blue 29 (AB29), Reactive Orange 16 (RO16) dan Reactive Red 120 (RR120) daripada larutan akues menggunakan Mg/Al dwi-hidroksida berlapis berkalsin (CLDH) dan tanpa kalsin (LDH) telah dilakukan menggunakan kaedah berkelompok pada suhu 25 °C. Penjerapan bahan pewarna menggunakan CLDH didapati lebih berkesan berbanding LDH. Penjerapan bahan pewarna oleh CLDH berlaku melibatkan proses penghidratan dan penstrukturan semula CLDH dan juga apitan AB29, RO16 dan RR120. Pencirian fizikal pada bahan penjerap yang diperolehi dengan menggunakan kaedah Pembelauan Sinar-X (XRD), Mikroskopi Imbasan Elektron (SEM) dan Spektroskopi Inframerah Transformasi Fourier (FTIR) telah digunakan untuk mengenalpasti fenomena 'kesan memori', iaitu proses penstrukturan semula kepada LDH selepas berlaku penghidratan. Cerapan lebih lanjut mengenai mekanisme proses penjerapan ini, model-model kinetik pseudo tertib pertama (PFO), pseudo tertib kedua (PSO) dan resapan intrapartikel (IPD) telah digunakan untuk menganalisis data ujian. Berdasarkan nilai pekali korelasi (R 2 ), model PSO didapati lebih sesuai (R 2 = 0.99 -1.00) berbanding PFO (R 2 = 0.85 -0.99). Fakta ini diperkukuhkan lagi dengan nilai kapasiti penjerapan maksimum, (q e ) hasil pengiraan menggunakan PSO yang didapati konsisten dengan q e ujian (q e, expt .) untuk AB29, RO16 dan RR120. Kitaran semula bahan penjerap melalui beberapa siri kitaran pengkalsinan-penstrukturan semula juga didapati dapat menjanjikan penjanaan semula CLDH.

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Section: Effect Of Contact Time and Initial Dye Concentrationsmentioning

confidence: 61%

Section: Effect Of Contact Time and Initial Dye Concentrationsmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

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ADSORPTION OF ANIONIC DYES FROM AQUEOUS SOLUTIONS BY CALCINED AND UNCALCINED Mg/Al LAYERED DOUBLE HYDROXIDE

Sumari

Hamzah

Kantasamy

2016

MJAS

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“…-1 due to the stretching mode of the structural -OH groups in the metal hydroxide. However, a small shoulder at 2900 -3000 cm -1 suggests the presence of a second type of -OH stretching vibration (possibly due to hydrogen bonding with carbonate in the interlayer spacing [26].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of fluoride removal from water by hydrotalcite-like compounds synthesized from the kaolinic clay

Hosni¹,

Srasra²

2011

J. Water Chem. Technol.

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“…The general formula is [M 1Àx 2+ M x 3+ (OH) 2 ] x+ A X/n nÀ mH 2 O, where M 2+ and M 3+ are the di-and trivalent metal cations, respectively, that occupy octahedral positions in the hydroxide layers, and A nÀ is an interlayer anion. 6,7 LDHs have been prepared with organic anions 8,9 and polymeric species anions. 10,11 LDHs have stronger interactions between the layers than silicates because of the higher charge density in the crystal structures that hinders the exfoliation of LDH nanolayers and the intercalation of polymer chains.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and characterization of an exfoliated modified syndiotactic polystyrene/Mg–Al-layered double-hydroxide nanocomposite

Jaymand

2010

Polym J

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This paper describes the synthesis and characterization of a controlled graft and block copolymerization onto syndiotactic polystyrene (sPS) using nitroxide-mediated living radical polymerization and the preparation of its polymer/layered doublehydroxide (LDH) nanocomposite. The graft and block copolymerization of styrene and p-methylstyrene were initiated with arylated sPS carrying 2,2,6,6-tetramethyl-1-piperidinyloxy groups as a macroinitiator. The structures of obtained graft and block copolymers were determined by 1 H nuclear magnetic resonance and Fourier transform infrared spectroscopy. The MgAl(Cl)-LDH precursor was prepared with microwave irradiation using a mixed solution of MgCl 2 and AlCl 3 , which was slowly pumped into decarbonated water. Thereafter, the surfactant-modified MgAl(SDBS) was obtained by the anion exchange reaction of MgAl(Cl)-LDH with sodium dodecyl benzene sulfate (SDBS). Finally, the sPS-g-(PS-b-PMS)/MgAl-LDH nanocomposite was prepared by a solution intercalation method. The exfoliated structure of the nanocomposite was probed by X-ray diffraction and transmission electron microscopy (TEM). Compared with pure sPS-g-(PS-b-PMS), the nanocomposite shows a much higher decomposition temperature and higher glass transition temperature. Keywords: functionalization; layered double hydroxide; living radical polymerization; modification; nanocomposite; syndiotactic polystyrene INTRODUCTIONRecently, there has been considerable interest in polymer/layered inorganic nanocomposites because of their different, often remarkably enhanced mechanical, thermal, electrical, optical and magnetic properties, which are rarely present in pure polymer or conventional composite. These enhanced properties are mainly attributed to the high degree of dispersion of layered inorganic compounds within the polymer matrix. 1-3 The layered materials include graphite and graphite oxide; metal chalcogenides such as molybdenum, titanium and lead sulfides; layered phosphates such as zirconium hydrogen phosphate; clays and layered silicates such as montmorillonite, hectorite and saponite; and layered double hydroxides (LDHs). 4,5 LDHs are a family of lamellar compounds that contain exchangeable ions in the interlayer space (anionic clays). The structure consists of brucite-like sheets with a typical thickness of 0.5 nm, in which the partial substitution of trivalent for divalent metallic ions results in a positive charge that is compensated by anions within the interlayer galleries. The general formula is [M 1Àx 2+ M x 3+ (OH) 2 ] x+ A X/n

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Preparation and characterization of Mg–Al hydrotalcite-like compounds containing cerium

Cited by 83 publications

References 22 publications

ADSORPTION OF ANIONIC DYES FROM AQUEOUS SOLUTIONS BY CALCINED AND UNCALCINED Mg/Al LAYERED DOUBLE HYDROXIDE

ADSORPTION OF ANIONIC DYES FROM AQUEOUS SOLUTIONS BY CALCINED AND UNCALCINED Mg/Al LAYERED DOUBLE HYDROXIDE

Evaluation of fluoride removal from water by hydrotalcite-like compounds synthesized from the kaolinic clay

Synthesis and characterization of an exfoliated modified syndiotactic polystyrene/Mg–Al-layered double-hydroxide nanocomposite

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