Phosphate Adsorption on Hematite, Kaolinite, and Kaolinite–Hematite (k–h) Systems As Described by a Constant Capacitance Model

Ioannou, A.; Dimirkou, A.

doi:10.1006/jcis.1997.4970

Cited by 68 publications

(62 citation statements)

References 24 publications

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“…[11][12][13] Although the adsorption capacity for inorganic anions onto kaolinite is relatively low when compared to iron oxides, kaolinite plays a certain role in the retention of inorganic uoride science it is widely distributed in natural environments. 8,11,12,14) Iron oxides and phyllosilicates are often simultaneously present in soils and sediments, where they tend to form binary systems by iron oxides coating on the surface of phyllosilicates. [13][14][15][16] The formation of iron oxide-phyllosilicate complexes has important in uences on the physical and chemical properties of the minerals in natural environments.…”

Section: Introductionmentioning

confidence: 99%

“…8,11,12,14) Iron oxides and phyllosilicates are often simultaneously present in soils and sediments, where they tend to form binary systems by iron oxides coating on the surface of phyllosilicates. [13][14][15][16] The formation of iron oxide-phyllosilicate complexes has important in uences on the physical and chemical properties of the minerals in natural environments. 13,14,17,18) The porous structure, surface area and cation exchange capacity (CEC) of the complexes are signi cantly different from the single phase phyllosilicates.…”

Section: Introductionmentioning

confidence: 99%

“…[13][14][15][16] The formation of iron oxide-phyllosilicate complexes has important in uences on the physical and chemical properties of the minerals in natural environments. 13,14,17,18) The porous structure, surface area and cation exchange capacity (CEC) of the complexes are signi cantly different from the single phase phyllosilicates. 14,17) In the binary systems iron oxides may accumulate on the negatively charged surface of phyllosilicates and thus decrease the negative charge density on phyllosilicates.…”

Section: Introductionmentioning

confidence: 99%

“…13,14,17,18) The porous structure, surface area and cation exchange capacity (CEC) of the complexes are signi cantly different from the single phase phyllosilicates. 14,17) In the binary systems iron oxides may accumulate on the negatively charged surface of phyllosilicates and thus decrease the negative charge density on phyllosilicates. 13,15) The point of zero charge (PZC) and the isoelectric point (IEP) of iron oxidephyllosilicate systems are signi cantly higher than those of the single phase phyllosilicates, and the increased magnitude depends on the type of iron oxides and the ratio of iron oxides to phyllosilicates.…”

Section: Introductionmentioning

confidence: 99%

“…13,15,17) Compared to phyllosilicates, iron oxide-coated phyllosilicates have a higher surface adsorption capacity for inorganic anions. 14,17,18) Fluoride adsorption onto minerals is an important process and can signi cantly affect the mobility and bioavailability of uorine in natural environments. 5,8,12) The adsorption characteristics for inorganic uoride by metal oxides or phyllosilicates have been extensively studied.…”

Section: Introductionmentioning

confidence: 99%

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Binary Systems of Kaolinite and Hematite: Preparation, Characterization and Adsorption Characteristics for Fluoride

et al. 2016

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In soils and sediments kaolinite (Kao) and hematite (Hem) are often cemented together as binary systems, which have a signi cant in uence on the mobility of nutrients and pollutants in natural environments. In this study, the binary systems of kaolinite-hematite complex (KHC) and kaolinite-hematite mixture (KHM) were prepared, and the surface properties and uoride adsorption of the samples were investigated. Compared to KHM, the XRD peaks for both kaolinite and hematite in KHC were lower. The crystallinity of hematite in KHM and KHC was 94.13% and 80.99% respectively. This indicates that the surface of kaolinite in KHC was largely coated by poorly crystalline hematite, and the coating in KHM was relatively weak. The total pore volume of the samples followed the sequence of Hem > KHC > KHM > Kao, and the speci c surface area (SSA) decreased in the order of KHC > Hem > KHM > Kao. The isoelectric point (IEP) of Kao, Hem, KHM and KHC was 3.3, 7.6, 5.9 and 6.5, and the zeta potential at pH 5.5 was −18.6, 25.3, 2.8 and 10.3 mV, respectively. The uoride adsorption data of the samples were tted using one-site Langmuir, two-site Langmuir and Freundlich models, and results indicated that the binary systems possessed the surface with various adsorption sites for uoride. At pH 5.5, the adsorption capacity (q max ) of Kao, Hem, KHM and KHC was 1.92, 13.79, 7.48 and 10.46 mg·g −1 , respectively. Compared to the average of Kao and Hem, the q max of KHC increased signi cantly (P < 0.05), whereas that of KHM had no signi cant change (P > 0.05).

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Binary Systems of Kaolinite and Hematite: Preparation, Characterization and Adsorption Characteristics for Fluoride

et al. 2016

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Editorial Comment

1998

Journal of Colloid and Interface Science

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It has come to our attention that a recent article (1) in this Journal contains extensive, verbatim quotations from Refs. 2-6. Because the quotations, which constitute approximately one-half of the text of Ref. 1, are not explicitly identified as such, it is appropriate to point out these unfortunate duplications and to acknowledge the priority of the original publications . This sort of duplication is inappropriate and unwelcome. Every effort is made to prevent such occurrences.

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Present and past bio-available phosphorus budget in the ultra-oligotrophic Lake Brienz

et al. 2007

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A detailed budget of the fluxes of bioavailable phosphorus (bio-P) was established for the ultra-oligotrophic Lake Brienz (Switzerland) and its catchment. Lake Brienz is a cold, deep oligotrophic peri-alpine lake that receives an annual load of approximately 300 kt of suspended sediments, mainly from two glacier-influenced rivers. The challenge was to overcome the associated high background of mineral-bound inorganic phosphorus (IP) of~200 t yr -1 that is mostly inaccessible to algae growth. The application of six complementary, independent datasets allowed a consistent balance of bio-P to be obtained. We made use of data on (a) the load imported by the contributing rivers, (b) net sedimentation from cores, (c) export of bio-P from catchment land to the surface waters estimated by a GIS model, (d) the downward flux of bio-P through the water column from sediment traps, (e) primary production, and (f) the mineralization rate of organic material from the consumption of oxidants in the uppermost sediment of the lake. The average bio-P load estimated from import measurements and net sedimentation is 7.0 t yr -1 with an error of about 10 %: An estimated 5.4 t yr -1 enters by way of the two main rivers (including 0.9 t yr -1 from sewage treatment plants), 1.2 t yr -1 from the remaining catchment (including 0.4 t yr -1 from sewage treatment plants that are diverted directly into the lake), and~1 t yr -1 from atmospheric deposition. Approximately 2 t of bio-P are retained annually in the sediments of the upstream dams and thereby withheld from downstream Lake Brienz. The maximum eutrophication of the lake in the late 1970s and the subsequent re-oligotrophication can be attributed to the loads of urban wastewater. The drop in biological productivity since the late 1970s is consistent with the decrease of bio-P fluxes archived in the sediment, the record of the sewage treatment plant outflows and the few occasional in-situ observations.

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Phosphate Adsorption on Hematite, Kaolinite, and Kaolinite–Hematite (k–h) Systems As Described by a Constant Capacitance Model

Cited by 68 publications

References 24 publications

Binary Systems of Kaolinite and Hematite: Preparation, Characterization and Adsorption Characteristics for Fluoride

Binary Systems of Kaolinite and Hematite: Preparation, Characterization and Adsorption Characteristics for Fluoride

Editorial Comment

Present and past bio-available phosphorus budget in the ultra-oligotrophic Lake Brienz

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