Removal mechanism of arsenate by bimetallic and trimetallic hydrocalumites depending on arsenate concentration

Takaki, Yu; Qiu, Xinhong; Hirajima, Tsuyoshi; Sasaki, Keiko

doi:10.1016/j.clay.2016.05.010

Cited by 15 publications

(5 citation statements)

References 39 publications

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“…According to previous research [17], the initial concentration of arsenate had a different impact on the adsorption of CaAl-LDH and CaMgAl-LDH, causing different removal mechanisms at different concentration ranges. Therefore, in addition to investigating the effect of initial borate concentrations on CaAl-LDH with different calcination temperatures, it is more important to explore the influence of Mg doping on these processes.…”

Section: The Effect Of Different Borate Concentrationsmentioning

confidence: 92%

“…The synthesis of CaAl-LDH and CaMgAl-LDH was carried out according to the method in our previous work [17,21]. The preparation of different LDHs was described in detail in Supplementary Materials Test S1.…”

Section: Preparation Of Ldhs and Calcined Ldhsmentioning

confidence: 99%

“…Moreover, we have discovered that the concentration of pollutants has a significant impact on the adsorption mechanism of CaAl-LDH and CaMgAl-LDH [17]. Utilizing various characterization techniques, we have identified at least three adsorption mechanisms of arsenate by these two LDHs: the intercalation, dissolution-reprecipitation (DR) reaction and surface complexation.…”

Section: Introductionmentioning

confidence: 99%

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The Role of Mg Doping in Manipulating the Adsorption Mechanisms of CaAl-Layered Double Hydroxide: Investigating the Effects of Calcination Temperature and Borate Concentration Changes

Xu,

Guo,

Sasaki

et al. 2023

Minerals

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CaAl-layered double hydroxides (LDHs) exhibit different mechanisms of borate removal at varying calcination temperatures. The addition of Mg alters the structure and composition of the calcined products, ultimately impacting their adsorption process. To investigate this, CaAl-LDH and Mg-doped CaAl-LDH with and without different calcination temperatures (500 °C and 900 °C) were prepared to immobilize a wide concentration range of borate. XRD, SEM, FTIR, and EXAFS techniques were employed to study the influence of Mg doping. The results indicate that the doping of Mg increases the BET surface area and enhances the adsorption capacity of uncalcined LDHs, with the enhancement being more pronounced at high borate concentrations. For LDHs calcined at 500 °C, Mg-doped LDHs exhibited slightly better adsorption at any borate concentration due to its more favorable ettringite formation. However, for LDHs calcined at 900 °C, Mg-doped LDHs (LDO) had a slightly better adsorption effect at low borate concentrations. At high concentrations, the crystallinity and morphology of the regenerated CaMgAl-LDH deteriorated, resulting in poor adsorption effects. These findings provide valuable theoretical support for understanding the mechanisms of removing pollutants with different concentrations by different LDHs.

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Section: The Effect Of Different Borate Concentrationsmentioning

confidence: 92%

Section: Preparation Of Ldhs and Calcined Ldhsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The Role of Mg Doping in Manipulating the Adsorption Mechanisms of CaAl-Layered Double Hydroxide: Investigating the Effects of Calcination Temperature and Borate Concentration Changes

Xu,

Guo,

Sasaki

et al. 2023

Minerals

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“…Hydrocalumite, Ca 2 Al(OH) 6 Cl•2H 2 O, belongs to the LDH family [21]. Among its most important applications are: adsorbent [24], antacid [25], ion-exchanger [26], and basic heterogeneous catalyst [27][28][29][30][31]. We recently reported the preparation of hydrocalumite from saline slags [8].…”

Section: Introductionmentioning

confidence: 99%

Preparation of Ca2Al1–mFem(OH)6Cl·2H2O-Doped Hydrocalumites and Application of Their Derived Mixed Oxides in the Photodegradation of Ibuprofen

et al. 2022

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Aluminum from saline slags generated during the recycling of this metal, extracted under reflux conditions with aqueous NaOH, was used in the synthesis of hydrocalumite-type solids with the formula Ca2Al1–mFem(OH)6Cl·2H2O. The characterization of the obtained solids was carried out by powder X-ray diffraction, infrared spectroscopy, thermal analysis, element chemical analysis, N2 adsorption-desorption at −196 °C and electron microscopy. The results showed the formation of Layered Double Hydroxide-type compounds whose characteristics varied as the amount of incorporated Fe3+ increased. These solids were calcined at 400 °C and evaluated for the catalytic photodegradation of ibuprofen, showing promising results in the elimination of this drug by advanced oxidation processes. The CaAl photocatalyst (without Fe) showed the best performance under UV light for the photodegradation of ibuprofen.

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“…According to Hibino and Tsuneshima, and Millanged et al, the structural memory effect of LDHs refers to a process of hydration and structural reconstruction of CLDHs. During this process, LDHs and their calcined materials have various possible adsorption mechanisms for pollutants, − including the following: (1) the metal solid solution interacts with pollutants during structural transformation, such as by surface complexation, (2) the pollutant molecules either are hosted between the layers of reconstructed LDH or located on the edges of LDHs, (3) due to its own solubility of newly formed LDHs, metal ions and pollutants form a new crystal phase through a dissolution–reprecipitation process.…”

Section: Introductionmentioning

confidence: 99%

Double-Edged Effect of Humic Acid on Multiple Sorption Modes of Calcined Layered Double Hydroxides: Inhibition and Promotion

Qiu

Sasaki

et al. 2019

Langmuir

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Layered double hydroxides (LDHs) are a typical class of anionic clay minerals whose structural memory effect has been widely used in pollutant adsorption. However, the influencing mechanism of humic acid (HA) on the structural memory effect in adsorption is not clear. In this study, HA was extracted from black soil and sediments, and its effect on the structural memory effect of LDHs with different divalent metals was evaluated in adsorption. Borate complexed with HAs and HAs promoted the dissolution of magnesiumcalcined LDHs (Mg-CLDH), which enhanced their adsorption rate by Mg-CLDH. However, the adsorbed HA caused a decline in the crystallinity of the regenerated Mg-LDH and an incomplete structural transformation, thereby resulting in decreased adsorption capacity. After the complexation of HAs with borate, the resulting compound was adsorbed on the surface of Zn-CLDH. The adsorption rate of borate was effectively improved in the initial stage, but at the same time slowed down the hydration and structural regeneration of Zn-CLDH. Meanwhile, the surface-adsorbed HAs also prevented borate from entering the newly formed layer inside the particles and led to a significant decrease in adsorption performance. When Ca-CLDH was used to adsorb borate, the process mainly occurred through the formation of ettringite. However, the presence of HAs enhanced the stability of the restructured LDHs and hindered the dissolution of Ca-CLDH and the reaction with B(OH) 4− to form ettringite during the regeneration process, which severely inhibited the sorption of borate.

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Removal mechanism of arsenate by bimetallic and trimetallic hydrocalumites depending on arsenate concentration

Cited by 15 publications

References 39 publications

The Role of Mg Doping in Manipulating the Adsorption Mechanisms of CaAl-Layered Double Hydroxide: Investigating the Effects of Calcination Temperature and Borate Concentration Changes

The Role of Mg Doping in Manipulating the Adsorption Mechanisms of CaAl-Layered Double Hydroxide: Investigating the Effects of Calcination Temperature and Borate Concentration Changes

Preparation of Ca2Al1–mFem(OH)6Cl·2H2O-Doped Hydrocalumites and Application of Their Derived Mixed Oxides in the Photodegradation of Ibuprofen

Double-Edged Effect of Humic Acid on Multiple Sorption Modes of Calcined Layered Double Hydroxides: Inhibition and Promotion

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