Reactive simulations of the activation barrier to dissolution of amorphous silica in water

Kagan, M.; Lockwood, Glenn K.; Garofalini, Stephen H.

doi:10.1039/c4cp00030g

Cited by 39 publications

(61 citation statements)

References 46 publications

(87 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…By using the dissociative watersilica potential developed by Mahadevan and Garofalini, 53 it was found that among the four (Q 4 → Q 3 , Q 3 → Q 2 , Q 2 → Q 1 , or Q 1 → Q 0 ) reactions, the Q 3 → Q 2 and Q 2 → Q 1 reactions have the highest activation energy of~14.1 kcal/mol, and is the rate limiting step in bulk silica dissolution. 19,24 These barriers are in the lower range of the experimental energy barriers of 14-24 kcal/mol and below values from cluster-based ab initio calculations (18-39 kcal/ mol). 19,24 Similar differences in energy barriers for siloxane bond breakage were identified by Du and de Leeuw on quartz surfaces.…”

Section: First-principles-based Simulations Of Glass-water Interactionsmentioning

confidence: 97%

“…19,24 These barriers are in the lower range of the experimental energy barriers of 14-24 kcal/mol and below values from cluster-based ab initio calculations (18-39 kcal/ mol). 19,24 Similar differences in energy barriers for siloxane bond breakage were identified by Du and de Leeuw on quartz surfaces. 67 Understanding how the local environment alters stability of siloxane bonds is critical to understanding how silica dissolves.…”

Section: First-principles-based Simulations Of Glass-water Interactionsmentioning

confidence: 97%

“…24 Due to the development of complex silica gel structures during dissolution, a single bond on a flat surface is not a realistic view of defect sites. For example, removal of 2-Ring defects decrease in nanoporous silica systems where defects are located on complex internal pore surfaces, affecting the reactivity of silica gel.…”

Section: First-principles-based Simulations Of Glass-water Interactionsmentioning

confidence: 99%

See 2 more Smart Citations

Atomistic computer simulations of water interactions and dissolution of inorganic glasses

Rimsza

2017

npj Mater Degrad

View full text Add to dashboard Cite

Computer simulations at the atomistic scale play an increasing important role in understanding the structure features, and the structure-property relationships of glass and amorphous materials. In this paper, we reviewed atomistic simulation methods ranging from first principles calculations and ab initio molecular dynamics (AIMD) simulations, to classical molecular dynamics (MD), and meso-scale kinetic Monte Carlo (KMC) simulations and their applications to study the reactions and interactions of inorganic glasses with water and the dissolution behaviors of inorganic glasses. Particularly, the use of these simulation methods in understanding the reaction mechanisms of water with oxide glasses, water-glass interfaces, hydrated porous silica gels formation, the structure and properties of multicomponent glasses, and microstructure evolution are reviewed. The advantages and disadvantageous of these simulation methods are discussed and the current challenges and future direction of atomistic simulations in glass dissolution presented.npj Materials Degradation (2017) 1:16 ; doi:10.1038/s41529-017-0017-yThe corrosion or degradation of glasses in aqueous solutions are critical in a number of engineering and technological processes ranging from microelectronic packaging, glass reaction chambers, and the immobilization of nuclear waste materials, as well as in healthcare and biomedical fields such as dissolution of inhaled glass fibers and bioactive glasses for biomedical applications. In particular, immobilizing radioactive waste in borosilicate glasses is widely accepted as a preferred method to treat nuclear waste materials generated from civilian and military sources. This process, also known as vitrification, is a critical component of the cycle of nuclear energy to combat global environmental and energy challenges. Researchers from around the world have extensively invested in understanding glass corrosion in an effort to predict the long-term stability and release rate radionuclides to the environment during nuclear waste storage. 1,2Various mechanisms for glass corrosion have been proposed and despite intensive experimental investigations with advanced characterization techniques results are unclear. It is generally accepted that the corrosion of glass consists of a set of complex processes including hydration, hydrolysis, and ion-exchange that are coupled during glass dissolution. The initial stage is interdiffusion of proton or hydronium ions from the solution with sodium or other alkali ions in the glass.3 This is followed by the hydrophilic attack of water on the Si-O-Si or Si-O-Al linkages that lead to hydroxylation of the silicate glass network. The remaining hydrolyzed glass skeleton then undergoes condensation and repolymerization to form the hydrated nanoporous silica rich gel layer which can be protective, decreasing dissolution to a residual rate. [4][5][6] The morphology of the gel layer, such as thickness, pore structure, and chemical composition, depends on the original glass composition and the pH...

show abstract

Section: First-principles-based Simulations Of Glass-water Interactionsmentioning

confidence: 97%

Section: First-principles-based Simulations Of Glass-water Interactionsmentioning

confidence: 97%

Section: First-principles-based Simulations Of Glass-water Interactionsmentioning

confidence: 99%

See 1 more Smart Citation

Atomistic computer simulations of water interactions and dissolution of inorganic glasses

Rimsza

2017

npj Mater Degrad

View full text Add to dashboard Cite

show abstract

“…use of a reactive potential is critical for analyzing all the reactions and material transport inside the glass and solution. Recent improvements of reactive MD force fields have allowed for several advances in the modeling of silica‐water interactions . In one of the most recent studies of sodium silicate hydration with the ReaxFF, leaching of sodium into water and accumulation at the interface of the leached Na + ions was observed along with proton transport inside the glass in the first nanosecond of reaction.…”

Section: Introductionmentioning

confidence: 99%

Hydration and reaction mechanisms on sodium silicate glass surfaces from molecular dynamics simulations with reactive force fields

Mahadevan

2020

J Am Ceram Soc

View full text Add to dashboard Cite

Recent development of reactive force fields have enabled molecular dynamics simulations of interactions between silicate glasses and water at the atomistic scale. While multicomponent silicate glasses encompass a wide variety of compositions and properties, one common structural feature in these glasses is the combination of the network structure that is made up of silica tetrahedra linked through corner sharing interspersed with network modifiers like alkali and alkaline‐earth ions that break up the Si–O–Si linkages by forming nonbridging oxygen. In reactions with water, ion exchange between alkali ions in the glass and proton or hydronium in the solution, as well as hydrolysis reaction of the Si–O–Si linkages and subsequent silanol formation, is observed and well documented. We have used a set of recently developed reactive force field to investigate the reactions between water and the surfaces of silica and sodium silicate glasses of different compositions for reactions up to 8 nanoseconds. Our results indicate sodium leaching into water and diffusion of water molecules up to 25 Å into the glass surface. We examined the structural and compositional changes inside the glass and around the diffused ions and use these to explain the rates of silanol formation at the surface. We also observed proton transport in the glass which has an indirect influence on the silanol formation rates. While the surface of the glass was rough to start with, it undergoes further modification into a hydrated gel‐like structure in the glass for up to 5 Å in the higher alkali containing glasses. It was found that the leached sodium ions remain close to the interface and that fragments of silicate network from the surface is capable of dislodging from the bulk glass and enter the aqueous solution. These simulations thus provide insights into the formation and structure of an alteration layers commonly observed in multicomponent silicate glasses corroded in aqueous solutions.

show abstract

“…Above 600°C, 100S undergoes extensive condensation of the Si-OH located at surface of the pores leaving the silica network exclusively composed of Q 4 species, whereas at 500°C (used here) a mixture of Q 2 ; Q 3 and Q 4 species was obtained [26,29,30]. When 100S was stabilised above 600°C, an activation energy barrier of 14-24 kcal mol À1 had to be crossed for the hydroxylation of the Q 4 species to occur prior to the release of silica, which in turn slowed down the dissolution [52][53][54].…”

Section: Effect Of the Crystallisation On The In Vitro Performancementioning

confidence: 99%

Lithium-silicate sol–gel bioactive glass and the effect of lithium precursor on structure–property relationships

Maçon

Jacquemin

Page

et al. 2016

J Sol-Gel Sci Technol

View full text Add to dashboard Cite

This work reports the synthesis of lithium-silicate glass, containing 10 mol% of Li 2 O by the sol-gel process, intended for the regeneration of cartilage. Lithium citrate and lithium nitrate were selected as lithium precursors. The effects of the lithium precursor on the sol-gel process, and the resulting glass structure, morphology, dissolution behaviour, chondrocyte viability and proliferation, were investigated. When lithium citrate was used, mesoporous glass containing lithium as a network modifier was obtained, whereas the use of lithium nitrate produced relatively dense glass-ceramic with the presence of lithium metasilicate, as shown by X-ray diffraction, 29 Si and 7 Li MAS NMR and nitrogen sorption data. Nitrate has a better affinity for lithium than citrate, leading to heterogeneous crystallisation from the mesopores, where lithium salts precipitated during drying. Citrate decomposed at a lower temperature, where the crystallisation of lithium-silicate crystal is not thermodynamically favourable. Upon decomposition of the citrate, a solid-state salt metathesis reaction between citrate and silanol occurred, followed by the diffusion of lithium within the structure of the glass. Both glass and glass-ceramic released silica and lithium ions in culture media, but release rate was lower for the glass-ceramic. Both samples did not affect chondrocyte viability and proliferation.Graphical Abstract

show abstract

Reactive simulations of the activation barrier to dissolution of amorphous silica in water

Cited by 39 publications

References 46 publications

Atomistic computer simulations of water interactions and dissolution of inorganic glasses

Atomistic computer simulations of water interactions and dissolution of inorganic glasses

Hydration and reaction mechanisms on sodium silicate glass surfaces from molecular dynamics simulations with reactive force fields

Lithium-silicate sol–gel bioactive glass and the effect of lithium precursor on structure–property relationships

Contact Info

Product

Resources

About