Lanthanide–humic substances complexation. I. Experimental evidence for a lanthanide contraction effect

Sonke, Jeroen E.; Salters, Vincent J. M.

doi:10.1016/j.gca.2005.11.017

Cited by 184 publications

(223 citation statements)

References 44 publications

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“…The chemical equilibrium modeling revealed that in the presence of humic substance a considerable part of the La got complexed with the humic substance. This is fully in line with several studies that have shown humic substance to be a strong complexing agent for lanthanides [42,70,71]. The modeling indicated that in the presence of humic acids La was complexed and otherwise would have precipitated with either hydroxyls or carbonate.…”

Section: Discussionsupporting

confidence: 90%

Effects of Dredging and Lanthanum-Modified Clay on Water Quality Variables in an Enclosure Study in a Hypertrophic Pond

Waajen

Engels²,

Oosterhout

2017

Water

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An enclosure experiment was conducted between July and September 2009 to compare the effectiveness of a phosphate fixative, the lanthanum-modified bentonite clay Phoslock ® (LMB), dredging, and their combination in controlling eutrophication in a hypertrophic urban pond in Heesch, The Netherlands. In total, 25 water quality variables were monitored. Multivariate analysis revealed that the combination LMB-treated and dredged enclosures deviated most from the pond (reference) and the controls, and showed the strongest eutrophication reduction. Overall, dredging significantly increased transparency, lowered turbidity, and improved the oxygen conditions in the enclosures compared to non-dredged ones. Nonetheless, one dredged enclosure deviated dramatically from the others, which might reflect methodological issues with dredging. The LMB treatment appeared to be less effective at mitigating eutrophication than dredging, and phosphate concentrations even increased during the experiment in the LMB-treated enclosures. Chemical equilibrium modeling suggested that humic substances could have formed complexes with lanthanum (La) from the LMB, rendering it unavailable for intercepting P over the course of the enclosure experiment. Residual lanthanum concentrations in combination dredging and LMB treatments exceeded the Dutch standard 10-fold. Total zooplankton abundance, and particularly Cladocera, increased in all enclosures over the course of the experiment. The limited effect of LMB in the enclosure experiment and the violation of the Dutch La standard when combined with dredging disqualify LMB as an intervention agent in the restoration of the pond.

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Section: Discussionsupporting

confidence: 90%

Effects of Dredging and Lanthanum-Modified Clay on Water Quality Variables in an Enclosure Study in a Hypertrophic Pond

Waajen

Engels²,

Oosterhout

2017

Water

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“…Eskenazy [32,33] proposed that the formation of organometallic compounds by sorption on the coagulating humic and fulvic might be the bound mechanism for REE and organic matters in coal. This idea is further confirmed by Sonke and Salters [34] and Wang et al [35]. We may assume that it is the replacement of metallic cations, such as Ca 2+ , Mg 2+ , etc., by REE cations in groups like -COOH or -OH that determines the affinity of REE to organic matter.…”

Section: Organic Affinities Of Trace Elementssupporting

confidence: 55%

Washability and Distribution Behaviors of Trace Elements of a High-Sulfur Coal, SW Guizhou, China

et al. 2018

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Abstract:The float-sink test is a commonly used technology for the study of coal washability, which determines optimal separation density for coal washing based on the desired sulfur and ash yield of the cleaned coal. In this study, the float-sink test is adopted for a high-sulfur Late Permian coal from Hongfa coalmine (No.26), southwestern Guizhou, China, to investigate its washability, and to analyze the organic affinities and distribution behaviors of some toxic and valuable trace elements. Results show that the coal is difficult to separate in terms of desulfurization. A cleaned coal could theoretically be obtained with a yield of 75.50%, sulfur 2.50%, and ash yield 11.33% when the separation density is 1.57 g/cm 3 . Trace elements' distribution behaviors during the gravity separation were evaluated by correlation analysis and calculation. It was found that Cs, Ga, Ta, Th, Rb, Sb, Nb, Hf, Ba, Pb, In, Cu, and Zr are of significant inorganic affinity; while Sn, Co, Re, U, Mo, V, Cr, Ni, and Be are of relatively strong organic affinity. LREE (Light rare earth elements), however, seem to have weaker organic affinity than HREE (Heavy rare earth elements), which can probably be attributed to lanthanide contraction. When the separation density is 1.60 g/cm 3 , a large proportion of Sn, Be, Cr, U, V, Mo, Ni, Cd, Pb, and Cu migrate to the cleaned coal, but most of Mn, Sb and Th stay in the gangue. Coal preparation provides alternativity for either toxic elements removal or valuable elements preconcentration in addition to desulfurization and deashing. The enrichment of trace elements in the cleaned coal depends on the predetermined separation density which will influence the yields and ash yields of the cleaned coal.

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“…First, based on the high dose that was applied and the reaction time needed for Phoslock Ò to bind PO 4 -P (van Oosterhout & Lürling, this volume), we can safely say that reaction time was adequate, but Phoslock Ò will not remove particulate P, or P in organisms such as algae. Second, the effectiveness of Phoslock Ò is reduced by interference of naturally occurring oxyanions other than phosphate (Johannesson & Lyons, 1994) or complex-forming humic substances (Tang & Johannesson, 2003Sonke & Salters, 2006). Inasmuch as the overall PO 4 -P and TP concentrations were only 30 and 18% lower in the claustrum compared with the reference site, both above mentioned reasons could have contributed to the Phoslock Ò -binding capacity being less than expected.…”

mentioning

confidence: 95%

Case study on the efficacy of a lanthanum-enriched clay (Phoslock®) in controlling eutrophication in Lake Het Groene Eiland (The Netherlands)

Lürling

Oosterhout

2012

Hydrobiologia

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Lake Het Groene Eiland was created in the beginning of 2008 by construction of dikes for isolating it from the surrounding 220-ha water body. This so-called claustrum of 5 ha was treated using lanthanum-modified clay (Phoslock Ò ) to control eutrophication and mitigate cyanobacterial nuisance. Cyanobacteria chlorophyll-a were significantly lower in the claustrum than those in the reference water body, where a massive bloom developed in summer, 2008. However, PO 4 -P and TP did not statistically differ in these two waters. TN and NO 3 -N were significantly lower in the claustrum, where dense submerged macrophytes beds developed. Lanthanum concentrations were elevated after the applications of the modified clay in the claustrum, but filterable lanthanum dropped rapidly below the Dutch standard of 10.1 lg l -1 . During winter, dozens of Canada geese resided at the claustrum. Geese droppings contained an average of 2 mg PO 4 -P g -1 dry weight and 12 mg NH 3 -N g -1 dry weight and might present a growing source of nutrients to the water. Constructing the claustrum enabled unrestricted bathing in subsequent three summers, as no swimming bans had to be issued due to cyanobacteria blooms. However, the role of the modified clay in this positive outcome remains unclear, and longevity of the measures questionable.

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Lanthanide–humic substances complexation. I. Experimental evidence for a lanthanide contraction effect

Cited by 184 publications

References 44 publications

Effects of Dredging and Lanthanum-Modified Clay on Water Quality Variables in an Enclosure Study in a Hypertrophic Pond

Effects of Dredging and Lanthanum-Modified Clay on Water Quality Variables in an Enclosure Study in a Hypertrophic Pond

Washability and Distribution Behaviors of Trace Elements of a High-Sulfur Coal, SW Guizhou, China

Case study on the efficacy of a lanthanum-enriched clay (Phoslock®) in controlling eutrophication in Lake Het Groene Eiland (The Netherlands)

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