Sorption/desorption of arsenate on/from Mg–Al layered double hydroxides: Influence of phosphate

Violante, A.; Pucci, Marianna; Cozzolino, Vincenza; Zhu, Jun; Pigna, Massimo

doi:10.1016/j.jcis.2009.01.004

Cited by 101 publications

(64 citation statements)

References 39 publications

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“…The X-ray diffractogram of the phosphate-loaded LDH ( Figure 20) was very different from that of the raw sample (Figure 2) as observed by: (i) the broad peak at 2θ = 25-50°, an implication of loss of order in the structure of the layered material after phosphate uptake (ii) significant reduction in the crystallinity of the spent samples, an indication of amorphous nature of the phosphate-laden LDH 2 . Mineralogical composition of the phosphate laden LDH 2 sample indicated the formation of whitlockite, hydroxyapatite (Ca 5 (PO 4 ) 3 .OH) and calcite [23][24]. Calcium -based LDHs are believed to exhibit this phenomenon due to formation of amorphous phosphate salts (precipitates) of Ca on the surface of the LDH sample during the sorption process [1].…”

Section: Characterisation Of Phosphate -Laden Ldhmentioning

confidence: 99%

Evaluation of Layered Double Hydroxide Synthesised from a Green Biogenic Precursor for Phosphate Removal: Characterisations and Isotherms

Adelagun¹

2017

AJBIO

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CaCr LDH materials were synthesized by the co-precipitation method, using Gastropod shell as a biogenic source of Ca 2+. The mineralogical, surficial morphology and elemental composition analysis of the materials showed characteristics typical of hydrotalcite-like materials, composed of Ca, Cr, O, C and Cl. Batch equilibrium adsorption studies showed that phosphate sorption on the LDH reached equilibrium within 5 min with about 98% removal. The sorption of phosphate was well described by the Langmuir isotherm model. The monolayer adsorption capacity of the CaCr LDH for phosphate was 142.86 mg/g. Mechanistic studies of phosphate removal by the LDHs was elucidated via instrumental analysis, vis-a viz, SEM-EDX, XRD and FTIR. Results revealed that phosphate was removed via the combination of ion exchange and precipitation. It could be inferred that CaCr LDH synthesised using Gastropod shell as a biogenic source of Ca 2+ is a suitable adsorbent for phosphate removal from aqua system.

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Section: Characterisation Of Phosphate -Laden Ldhmentioning

confidence: 99%

Evaluation of Layered Double Hydroxide Synthesised from a Green Biogenic Precursor for Phosphate Removal: Characterisations and Isotherms

Adelagun¹

2017

AJBIO

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“…pH, reaction time, surface coverage and, last but not least, sequence of addition of the anions. 29,30 Violante and coworkers 29 showed that the final arsenate adsorbed/phosphate adsorbed molar ratio increased by adding arsenate before phosphate, but decreased by adding phosphate before arsenate. Since in our experiments phosphate was always added into arsenate solution it is not surprising the influence of phosphate on arsenate adsorption is not large.…”

Section: The Influence Of Phosphate On Arsenic Adsorptionmentioning

confidence: 99%

Adsorption of Arsenic on MgAl Layered Double Hydroxide

et al. 2013

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Abstract. Groundwater in the Eastern Croatia, as well in the South-eastern Hungary, contains relatively high concentrations of arsenic that can cause chronic toxicity to humans. Therefore, the aim to find an effective composite adsorbent that can be applied for arsenic water remediation by introducing it in the groundwater treatment is very important. The presented results were obtained using layered double hydroxide (LDH) as a sorbing system. MgAl LDH samples with a Mg:Al molar ratio of 2:1 were synthesized. Adsorption of arsenic anions from groundwater samples from Eastern Croatia, as well as adsorption of model aquatic arsenic sample solutions, on MgAl layered double hydroxide was investigated. Inductively coupled plasma atomic emission spectrometry (ICP-AES) was used for determination of arsenic concentration after adsorption. It was shown that in both cases the adsorption process could be interpreted in terms of Kroeker adsorption isotherm regardless to the presence of other ions in the groundwater. Additionally, the influence of phosphate concentration on adsorption of model arsenic samples was examined and it was shown that (at least in examined range of arsenic and phosphate concentration) there is no significant influence of phosphate on adsorption of arsenic.

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“…Layered double hydroxides (LDHs) have the potential to remove oxyanion water contaminants such as arsenate [8,[28][29][30][31], chromate [32][33][34], and phosphate [3,[35][36][37][38][39] due to its large specific surface areas and high anion exchange capacity. LDHs, also known as hydrotalcite-like compounds or anionic clays, are a class of layered minerals with exchangeable anions in the gallery spaces [40].…”

Section: Introductionmentioning

confidence: 99%

“…Yang et al [41] found that the adsorption rate of arsenate onto LDHs increases with decreasing LDH particle size, while the adsorption capacity is independent of the particle size. Violante et al [30] demonstrated that phosphate has a greater affinity to LDHs than arsenate. These experiments have focused on the influence on the adsorptions of As from layer charge density, different LDHs, particles sizes, and competitive adsorption from other anions.…”

Section: Introductionmentioning

confidence: 99%

Interlayer Structures and Dynamics of Arsenate and Arsenite Intercalated Layered Double Hydroxides: A First Principles Study

Zhang¹,

Liu²,

Zhang³

et al. 2017

Minerals

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Abstract:In this study, by using first principles simulation techniques, we explored the basal spacings, interlayer structures, and dynamics of arsenite and arsenate intercalated Layered double hydroxides (LDHs). Our results confirm that the basal spacings of NO 3 − -LDHs increase with layer charge densities. It is found that Arsenic (As) species can enter the gallery spaces of LDHs with a Mg/Al ratio of 2:1 but they cannot enter those with lower charge densities. Interlayer species show layering distributions. All anions form a single layer distribution while water molecules form a single layer distribution at low layer charge density and a double layer distribution at high layer charge densities. H 2 AsO 4 − has two orientations in the interlayer regions (i.e., one with its three folds axis normal to the layer sheets and another with its two folds axis normal to the layer sheets), and only the latter is observed for HAsO 4 2− . H 2 AsO 3 − orientates in a tilt-lying way. The mobility of water and NO 3 − increases with the layer charge densities while As species have very low mobility.Our simulations provide microscopic information of As intercalated LDHs, which can be used for further understanding of the structures of oxy-anion intercalated LDHs.

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Sorption/desorption of arsenate on/from Mg–Al layered double hydroxides: Influence of phosphate

Cited by 101 publications

References 39 publications

Evaluation of Layered Double Hydroxide Synthesised from a Green Biogenic Precursor for Phosphate Removal: Characterisations and Isotherms

Evaluation of Layered Double Hydroxide Synthesised from a Green Biogenic Precursor for Phosphate Removal: Characterisations and Isotherms

Adsorption of Arsenic on MgAl Layered Double Hydroxide

Interlayer Structures and Dynamics of Arsenate and Arsenite Intercalated Layered Double Hydroxides: A First Principles Study

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