Layered Double Hydroxide and Its Calcined Product for Fluoride Removal from Groundwater of Ethiopian Rift Valley

Dessalegne, Meseret; Zewge, Feleke; Pfenninger, Numa; Johnson, C. Annette; Dı́az, Isabel

doi:10.1007/s11270-016-3079-5

Cited by 31 publications

(19 citation statements)

References 32 publications

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“…Industrial recycling of fluoride is globally very limited, with fluoride-bearing waste streams generally viewed as nuisances to dispose of, rather than recycling opportunities [4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Towards the implementation of an ion-exchange system for recovery of fluoride commodity chemicals. Kinetic and dynamic studies

Robshaw

Dawson

Bonser

2019

Chemical Engineering Journal

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“…Industrial recycling of fluoride is globally very limited, with fluoride-bearing waste streams generally viewed as nuisances to dispose of, rather than recycling opportunities [4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Towards the implementation of an ion-exchange system for recovery of fluoride commodity chemicals. Kinetic and dynamic studies

Robshaw

Dawson

Bonser

2019

Chemical Engineering Journal

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“…However, the sorption data did not fit for the calculation of the isotherm because, due to the complexity of the SU1 chemical composition, also other processes, like the precipitation of calcium carbonates, occurred during the interaction between water and calcined LDHs having an effect on the Sb removal. It is worth mentioning that the LDHs exhibit the possibility of being reused by regeneration, operated through calcination or anion exchange, for consecutive sorption-regeneration-sorption cycles [50][51][52][53][54]. This is a very important characteristic for their practical use in water treatment because it can reduce the amount of post-treatment waste materials.…”

Section: Sorption Experiments With Su Suergiu Mine Drainage (Su1)mentioning

confidence: 99%

Antimonate Removal from Polluted Mining Water by Calcined Layered Double Hydroxides

2019

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Calcined layered double hydroxides (LDHs) can be used to remove Sb(V), in the Sb(OH)6− form, from aqueous solutions. Sorption batch experiments showed that the mixed MgAlFe oxides, obtained from calcined hydrotalcite-like compound (3HT-cal), removed Sb(OH)6− through the formation of a non-LDH brandholzite-like compound, whereas the mixed ZnAl oxides, resulting from calcined zaccagnaite-like compound (2ZC-cal), trapped Sb(OH)6− in the interlayer during the formation of a Sb(V)-bearing LDH (the zincalstibite-like compound). The competition effect of coexistent anions on Sb(OH)6− removal was HAsO42− >> HCO3− ≥ SO42− for 2ZC-cal and HAsO42− >> HCO3− >> SO42− for 3HT-cal. Considering the importance of assessing the practical use of calcined LDHs, batch experiments were also carried out with a slag drainage affected by serious Sb(V) pollution (Sb = 9900 μg/L) sampled at the abandoned Su Suergiu mine (Sardinia, Italy). Results showed that, due to the complex chemical composition of the slag drainage, dissolved Sb(OH)6− was removed by intercalation in the interlayer of carbonate LDHs rather than through the formation of brandholzite-like or zincalstibite-like compounds. Both 2ZC-cal and 3HT-cal efficiently removed very high percentages (up to 90–99%) of Sb(V) from the Su Suergiu mine drainage, and thus can have a potential application for real polluted waters.

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“…Commonly used technologies of defluoridation involve the use of adsorbents either aluminium or calcium phosphate based. As anion exchangers, hydrotalcites (also called layered double hydroxides or LDH) are also potential high capacity materials [25,26]. We investigated the fluoride uptake by layered double hydroxide (LDH) and calcined layered double hydroxide (CLDH).…”

Section: Defluoridation Of Drinking Watermentioning

confidence: 99%

Environmental uses of zeolites in Ethiopia

Dı́az

2017

Catalysis Today

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In the past six years we have been intensively collaborating with the Chemistry Department of Addis Ababa University as well as Haramaya University to bust scientific knowledge related to zeolites and zeolite applications. Initially, we teamed up with geologists and government actors in the mining sectors; as a result we got access to natural zeolites from the north of the country, as well as other industrial minerals such as kaolin. In parallel we developed research activities in the use of zeolites as adsorbents and in catalytic processes related to environmental applications of necessity in Ethiopia. In the first part of this paper I will describe two examples of adsorption processes using mineral resources: one is a natural stilbite used to develop an adsorbent to remove fluoride from drinking waters; and the second one uses virgin kaolin to prepare a synthetic zeolite 4A that we used to remove chromium from tannery wastewaters. Finally, two catalytic examples will be described: in the first one we tackled the photocatalytic degradation of dyes from textile industries using Ti-modified natural and synthetic zeolites, and in the second one we used modified mordenites, both natural and synthetic, for the conversion of glucose into 5-HMF.

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Layered Double Hydroxide and Its Calcined Product for Fluoride Removal from Groundwater of Ethiopian Rift Valley

Cited by 31 publications

References 32 publications

Towards the implementation of an ion-exchange system for recovery of fluoride commodity chemicals. Kinetic and dynamic studies

Towards the implementation of an ion-exchange system for recovery of fluoride commodity chemicals. Kinetic and dynamic studies

Antimonate Removal from Polluted Mining Water by Calcined Layered Double Hydroxides

Environmental uses of zeolites in Ethiopia

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