Effects of CO2 and temperature on phytolith dissolution

Nguyen, Thi Ngoc Anh; Nguyen, Anh Gia-Tuan; Nguyen, Ly N.; Nguyen, Huan X.; Tran, Tien Minh; Tran, Phong D.; Dultz, Stefan; Nguyen, Minh N.

doi:10.1016/j.scitotenv.2021.145469

Cited by 18 publications

(12 citation statements)

References 62 publications

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“…The encapsulation of nutrients was simply a physical process; however, the association of organic matter and silica wall might be strengthened by chemical bonds. The occurrences of Si-C and Si-O-K bonds have been reported in previous studies (Pan et al 2017;Nguyen et al 2020;Nguyen et al 2021a). This means that both physical and chemical processes can simultaneously affect the encapsulation of organic matter and nutrients in plant transport sap into phytolith structure.…”

Section: Discussionsupporting

confidence: 75%

“…Their direct dissolution can be an additional process that serves for the release of free ions into the solution. Releases of alkaline nutrients (e.g., Ca, Mg and K) can alleviate the effects of CO 2 because they act against the reduction of pH, activate the conversion of CO 2 into anionic species, HCO 3 − and CO 3 2− , favour the adsorption of the anionic species on phytolith surface at which the anionic species can stimulate the dissolution of the phytolith ashes (Nguyen et al 2021a). However, in the sense of this study, CO 2 was continuously supported.…”

Section: Discussionmentioning

confidence: 99%

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The Regulatory Role of CO2 on Nutrient Releases from Rice-Straw Phytoliths

Nguyen

et al. 2022

Preprint

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Phytolith has been widely known as a porous silica structure in numerous silicon (Si) accumulator plants, e.g., rice, that contain various nutrients and other beneficial elements too. When rice straw is returned to paddy fields, the silica structure of phytolith can be dissolved, thereby releasing its occluded nutrients. While the intrinsic characteristics and dissolution properties of phytoliths under the effect of solution chemistry have been intensively studied, the effect of gas phases, especially CO2, on phytolith stability and the implications for nutrient release are not fully known. Here, dissolution properties of phytolith ashes obtained from dry ashing of rice straw at 400, 600 and 800οC were investigated by quantifying Si release together with other nutrients under two atmospheric conditions, i.e., without and with CO2 support (aeration). In a time span of 6 days, the releases of nutrients (K, P, Ca, Mg) showed high dependence on the overall dissolution of the phytolith ashes. CO2 significantly reduced the dissolution rate of the phytolith ashes but increased the release rates of cationic as well as anionic nutrients. The aeration of CO2 shifted the carbonate equilibrium (H2CO3, HCO3− and CO32−) towards H2CO3, reducing solution pH, thereby decreasing the dissolution rate of phytoliths. Following this, intensification of H+ exchange promoted vast evacuation of cationic nutrients from the phytolith ashes. This indicates contrast responses of phytoliths and their occluded nutrients to CO2, and provides a better insight on the fate of soil phytoliths and the tendency of nutrient budgets from rice straw phytoliths in soils.

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Section: Discussionsupporting

confidence: 75%

Section: Discussionmentioning

confidence: 99%

The Regulatory Role of CO2 on Nutrient Releases from Rice-Straw Phytoliths

Nguyen

et al. 2022

Preprint

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“…8,9 The dissolution of the phytolith is mutually governed by the intrinsic nature of phytoliths [10][11][12] and as well as solution chemistry. 9,10,13 This explains why a wide range of dissolution rates has been reported in recent phytolith studies. 14,15 The half-life of phytoliths is commonly found to range between 6 months and 3 years, 10 but it can be significantly shorter for ashed phytoliths (those obtained from open burning or heat treatment).…”

mentioning

confidence: 81%

“…This process activates the disassociation of Si in the form of monomeric silicic acid, eventually destroying the phytolith body 8,9 . The dissolution of the phytolith is mutually governed by the intrinsic nature of phytoliths 10–12 and as well as solution chemistry 9,10,13 . This explains why a wide range of dissolution rates has been reported in recent phytolith studies 14,15 .…”

Section: Introductionmentioning

confidence: 99%

Potassium in silicon‐rich biomass wastes: A perspective of slow‐release potassium sources

Nguyen

vụ

et al. 2022

Biofuels Bioprod Bioref

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Many plant species that are known as silicon (Si) accumulators can form a so-called phytolith (silicified structure) within their organs. Together with organic matter, potassium (K) has also been found in phytolith structures (phytK). Annually, billions of tons of Si-rich biomass wastes are cycled in agricultural and natural systems worldwide. However, the fate of the phytolith and its phytK have not been fully understood. This study aims to examine the dynamic release of phytK from phytoliths of reed, rice straw, maize and sugarcane leaf samples. Phytoliths obtained from the biomasses by performing heat treatment at 600 °C were used for batch kinetic experiments. The phytK was found to have 26.3 ± 10.6, 98.9 ± 17.4, 24.9 ± 14.8 and 58.8 ± 13.9 mg Kg −1 for the reed, rice straw, sugarcane and maize leaves, respectively. These phytK amounts comprised at least >45% of the total K budgets in the biomasses and they were observed to be gradually released with time. The retardation of phytK was tightly related to the dissolution rate of phytoliths. The findings highlight that phytoliths carry certain amounts of K, potentially serving as a slow-release K source for soil and crops. Additionally, this short communication suggests a premise for the development of refinery strategies or extending the range of agronomic options for billions of tons of Si-rich biomass wastes worldwide.

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“…Plants with high phytolith carbon sequestration rates play an important role in increasing the global carbon sink and mitigating global CO 2 emissions (Chen et al, 2019;Meng et al, 2013;Song et al, 2017). However, the combustion of plants might influence the chemical composition of phytoliths and their taphonomy in soils (Blecker et al, 2006;Nguyen and Nguyen, 2019;Nguyen et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

Burned phytoliths absorbing black carbon as a potential proxy for paleofire

Dong

Wei

et al. 2022

The Holocene

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Developing and refining fire proxies is paramount for reliable reconstructions and the inferences that they gain about fire in the Earth System. Burned phytolith index is an important tool for fire reconstruction. However, the source of the darkened color which appears on burned phytoliths is controversial and requires additional study to understand the relationship between phytolith characteristics and fire activity. By simulating burning of six grass species under open conditions, we extracted phytoliths from the ashes using a microwave digestion method. Then, we measured the carbon content of the ashed phytolith and the unburned phytolith (from modern plant). Next, we measured the carbon content of burned phytolith when treated with bleach. Our results show that the carbon contents of ashed phytoliths are higher than phytoliths extracted from plants, and ashed phytoliths after bleaching. The increased carbon content probably resulted from adsorption of black carbon by phytoliths exposed to open flames. We conclude that phytolith- related carbon might be a potential indicator of paleofire using soils and sediments.

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Effects of CO2 and temperature on phytolith dissolution

Cited by 18 publications

References 62 publications

The Regulatory Role of CO2 on Nutrient Releases from Rice-Straw Phytoliths

The Regulatory Role of CO2 on Nutrient Releases from Rice-Straw Phytoliths

Potassium in silicon‐rich biomass wastes: A perspective of slow‐release potassium sources

Burned phytoliths absorbing black carbon as a potential proxy for paleofire

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