Chemical composition of plant silica phytoliths

Kameník, Jan; Mizera, Jiří; Řanda, Z.

doi:10.1007/s10311-012-0396-9

Cited by 66 publications

(47 citation statements)

References 19 publications

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“…This is followed by removal of acid‐soluble components using HCl and residual organic material by oxidation with H 2 O 2 . Wet ashing relies on digestion of organic material by HNO 3 and simultaneous oxidation by KClO 3 , and is sufficient for comparing biogenic silica morphology, for example, but leaves significant amounts of residual undigested organic material, yielding silica concentrations as low as 3% for some substrates . The advantage of this method is that high temperatures are avoided so that no changes in the physical properties (e.g.…”

Section: Silica In Grassesmentioning

confidence: 99%

“…35,40 The reversible interaction increases solubility of silica by allowing high surface silanol concentrations, while the irreversible interaction presented in (b) cause decreased solubility of silica, presumably because the negative aluminium substitutions repel the catalyst for depolymerization, OH -. 53 Silica content will in general be overestimated, and the degree of overestimation will depend on the substrate and exact procedures. Direct comparison between studies therefore needs to be done with care.…”

Section: Silica Interactions With Organic Moleculesmentioning

confidence: 99%

“…refractive index and size) occur. 54 On the contrary, these changes occur in dry ashing, 54 but since it produces higher purity (87-99.5%) 53 this method is more suitable for determining silica contents in…”

Section: Silica Contentsmentioning

confidence: 99%

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Implications of silica on biorefineries – interactions with organic material and mineral elements in grasses

Sørensen

Knudsen

et al. 2014

Biofuels Bioprod Bioref

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Biorefineries aim to convert low value biomasses into high value products. The feedstock biomasses are often high‐silica agricultural waste products such as rice straw, wheat straw, corn stover, sugarcane bagasse, or empty fruit bunches. This causes challenges, since silica is problematic in industrial processes, where it forms water‐insoluble precipitates that are hard to remove, block filtration systems, and cause instrumental defects. In this paper we review various industries that experience issues with silica. These include paper pulping and waste‐water treatment, where they try to solve their problems with silica in different ways. High pH and co‐precipitation with mineral elements are some common ways of alleviating silica problems. Reviewing the literature for the fundamentals of silica revealed a complex chemistry that is not yet fully understood. Much is still to be learned about the interactions between silica and organic material as well as the mechanisms of silica precipitation and dissolution. Understanding the fundamental and complex chemistry of silica might help developing better solutions than those existing today, allowing efficient use of high silica biomasses in biorefineries. © 2014 Society of Chemical Industry and John Wiley & Sons, Ltd

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Section: Silica In Grassesmentioning

confidence: 99%

Section: Silica Interactions With Organic Moleculesmentioning

confidence: 99%

See 1 more Smart Citation

Implications of silica on biorefineries – interactions with organic material and mineral elements in grasses

Sørensen

Knudsen

et al. 2014

Biofuels Bioprod Bioref

View full text Add to dashboard Cite

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“…Evidence suggests that sequestration associated with BSi alone can be large. We know that vegetation BSi structures can incorporate relatively large amounts of trace elements (Kameník et al 2013), although whether the same is true for siliceous organisms that actively uptake DSi is unclear. Preliminary work by Emoto et al (2013) shows marine diatom BSi has elemental concentrations at levels close to the concentrations of the continental crust, which is much higher than expected.…”

Section: Implications For Weathering Rate Calculationmentioning

confidence: 99%

Lack of steady-state in the global biogeochemical Si cycle: emerging evidence from lake Si sequestration

et al. 2014

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Weathering of silicate minerals releases dissolved silicate (DSi) to the soil-vegetation system. Accumulation and recycling of this DSi by terrestrial ecosystems creates a pool of reactive Si on the continents that buffers DSi export to the ocean. Human perturbations to the functioning of the buffer have been a recent research focus, yet a common assumption is that the continental Si cycle is at steadystate. However, we have no good idea of the timescales of ecosystem Si pool equilibration with their environments. A review of modelling and geochemical considerations suggests the modern continental Si cycle is in fact characterised in the longterm by an active accumulation of reactive Si, at least partially attributable to lakes and reservoirs. These lentic systems accumulate Si via biological conversion of DSi to biogenic silica (BSi). An analysis of new and published data for nearly 700 systems is presented to assess their contribution to the accumulating continental pool. Surface sediment BSi concentrations (n = 692) vary between zero and [60 % SiO 2 by weight, apparently independently of lake size, location or water chemistry. Using sediment core BSi accumulation rates (n = 109), still no relationships are found with lake or catchment parameters. However, issues associated with single-core accumulation rates should in any case preclude their use in elemental accumulation calculations. Based on lake/reservoir mass-balances (n = 34), our best global-scale estimate of combined lake and reservoir Si retention is 1.53 TMol year -1 , or 21-27 % of river DSi export. Again, no scalable relationships are apparent, suggesting Si retention is a complex process that varies from catchment to catchment. The lake Si sink has implications for estimation of weathering flux generation from river chemistry. The size of the total continental Si pool is poorly constrained, as is its accumulation rate, but lakes clearly contribute substantially. A corollary to this emerging understanding is that the flux and isotopic composition of DSi delivered to the ocean has likely varied over time, partly mediated by a fluctuating continental pool, including in lakes.

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“…no Al release from the biogenic fraction. This leads to an overestimation of Al as small amounts (< 0.05 wt %) of Al are found in phytoliths and diatoms (Kameník et al, 2013;Van Cappellen et al, 2002). The Si coming from shards can then be calculated by substitution:…”

Section: Discerning a Shard Signature From Biogenic Si Alkmentioning

confidence: 99%

The contribution of tephra constituents during biogenic silica determination: implications for soil and palaeoecological studies

et al. 2015

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Abstract. Biogenic silica (BSi) is used as a proxy by soil scientists to identify biological effects on the Si cycle and by palaeoecologists to study environmental changes. Alkaline extractions are typically used to measure BSi in both terrestrial and aquatic environments. The dissolution properties of volcanic glass in tephra deposits and their nanocrystalline weathering products are hypothesized to overlap those of BSi; however, data to support this behaviour are lacking. The potential that Si-bearing fractions dissolve in alkaline media (Si Alk ) that do not necessarily correspond to BSi brings the applicability of BSi as a proxy into question. Here, analysis of 15 samples reported as tephra-containing allows us to reject the hypothesis that tephra constituents produce an identical dissolution signal to that of BSi during alkaline extraction. We found that dissolution of volcanic glass shards is incomplete during alkaline dissolution. Simultaneous measurement of Al and Si used here during alkaline dissolution provides an important parameter to enable us to separate glass shard dissolution from dissolution of BSi and other Si-bearing fractions. The contribution from volcanic glass shards (between 0.2 and 4 wt % SiO 2 ), the main constituent of distal tephra, during alkaline dissolution can be substantial depending on the total Si Alk . Hence, soils and lake sediments with low BSi concentrations are highly sensitive to the additional dissolution from tephra constituents and its weathering products. We advise evaluation of the potential for volcanic or other non-biogenic contributions for all types of studies using BSi as an environmental proxy.

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Chemical composition of plant silica phytoliths

Cited by 66 publications

References 19 publications

Implications of silica on biorefineries – interactions with organic material and mineral elements in grasses

Implications of silica on biorefineries – interactions with organic material and mineral elements in grasses

Lack of steady-state in the global biogeochemical Si cycle: emerging evidence from lake Si sequestration

The contribution of tephra constituents during biogenic silica determination: implications for soil and palaeoecological studies

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