Use of coupled passivants and consolidants on calcite mineral surfaces

Nagy, K L; Cygan, R T; Brinker, C J; Ashley, C S; Scotto, C S

Title: Use of coupled passivants and consolidants on calcite mineral surfaces

Full Record
Other Related Research

Abstract

Deterioration of monuments, buildings, and works of art constructed of carbonate-based stone potentially can be arrested by applying a combination of chemical passivants and consolidants that prevent hydrolytic attack and mechanical weakening. The authors used molecular modeling and laboratory synthesis to develop an improved passivating agent for the calcite mineral surface based on binding strength and molecular packing density. The effectiveness of the passivating agent with and without a linked outer layer of consolidant against chemical weathering was determined through leaching tests conducted with a pH-stat apparatus at pH 5 and 25 C. For the range of molecules considered, modeling results indicate that the strongest-binding passivant is the trimethoxy dianionic form of silylalkylaminocarboxylate (SAAC). The same form of silylalkylphosphonate (SAP) is the second strongest binder and the trisilanol neutral form of aminoethylaminopropylsilane (AEAPS) is ranked third. Short-term leaching tests on calcite powders coated with the trisilanol derivative of SAAC, the triethoxy neutral form of SAP, and the trimethoxy neutral form of AEAPS show that the passivant alone does not significantly slow the dissolution rate. However, all passivants when linked to the sol consolidant result in decreased rates. Combined AEAPS plus consolidant results in a coating that performs better than themore »« less

Authors:

Nagy, K L; Cygan, R T; Brinker, C J; Ashley, C S ^[1]; Scotto, C S ^[2]

Sandia National Labs., Albuquerque, NM (United States)
Naval Research Lab., Washington, DC (United States). Optical Sciences Div.

Publication Date:: 1997-02-01

Research Org.:: Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

Sponsoring Org.:: USDOE, Washington, DC (United States)

OSTI Identifier:: 441661

Report Number(s):: SAND-97-0239C; CONF-961202-40
ON: DE97002531; TRN: AHC29705%%6

DOE Contract Number:: AC04-94AL85000

Resource Type:: Conference

Resource Relation:: Conference: 1996 Fall meeting of the Materials Research Society (MRS), Boston, MA (United States), 2-6 Dec 1996; Other Information: PBD: [1997]

Country of Publication:: United States

Language:: English

Subject:: 36 MATERIALS SCIENCE; CALCITE; CORROSION PROTECTION; BUILDING MATERIALS; CULTURAL OBJECTS; CORROSION INHIBITORS; PROTECTIVE COATINGS; WEATHERING; MATERIALS TESTING; PASSIVATION; MOLECULAR MODELS

Citation Formats


                    Nagy, K L, Cygan, R T, Brinker, C J, Ashley, C S, and Scotto, C S. Use of coupled passivants and consolidants on calcite mineral surfaces.  United States: N. p., 1997. 
        Web.

Copy to clipboard


                    Nagy, K L, Cygan, R T, Brinker, C J, Ashley, C S, & Scotto, C S. Use of coupled passivants and consolidants on calcite mineral surfaces.  United States.

Copy to clipboard


                    Nagy, K L, Cygan, R T, Brinker, C J, Ashley, C S, and Scotto, C S. 1997.  
        "Use of coupled passivants and consolidants on calcite mineral surfaces".  United States.  https://www.osti.gov/servlets/purl/441661.

Copy to clipboard


                    
@article{osti_441661,

  title        = {Use of coupled passivants and consolidants on calcite mineral surfaces},

  author       = {Nagy, K L and Cygan, R T and Brinker, C J and Ashley, C S and Scotto, C S},

  abstractNote = {Deterioration of monuments, buildings, and works of art constructed of carbonate-based stone potentially can be arrested by applying a combination of chemical passivants and consolidants that prevent hydrolytic attack and mechanical weakening. The authors used molecular modeling and laboratory synthesis to develop an improved passivating agent for the calcite mineral surface based on binding strength and molecular packing density. The effectiveness of the passivating agent with and without a linked outer layer of consolidant against chemical weathering was determined through leaching tests conducted with a pH-stat apparatus at pH 5 and 25 C. For the range of molecules considered, modeling results indicate that the strongest-binding passivant is the trimethoxy dianionic form of silylalkylaminocarboxylate (SAAC). The same form of silylalkylphosphonate (SAP) is the second strongest binder and the trisilanol neutral form of aminoethylaminopropylsilane (AEAPS) is ranked third. Short-term leaching tests on calcite powders coated with the trisilanol derivative of SAAC, the triethoxy neutral form of SAP, and the trimethoxy neutral form of AEAPS show that the passivant alone does not significantly slow the dissolution rate. However, all passivants when linked to the sol consolidant result in decreased rates. Combined AEAPS plus consolidant results in a coating that performs better than the commercial product Conservare{reg_sign} OH and at least as well as Conservare{reg_sign} H. The modeling results indicate that there may be a threshold binding energy for the passivant above which the dissolution rate of calcite is actually enhanced. More strongly-binding passivants may aid in the dissolution mechanism or dissociate in aqueous solution exposing the calcite surface to water.},

  doi          = {},

  url          = {https://www.osti.gov/biblio/441661},
  journal      = {},
number       = ,

  volume       = ,

  place        = {United States},

  year         = {1997},

  month        = {2}

}

Copy to clipboard

Conference:

View Conference (0.57 MB)

Other availability

Please see Document Availability for additional information on obtaining the full-text document. Library patrons may search WorldCat to identify libraries that hold this conference proceeding.

Save / Share:

Export Metadata

Save to My Library

Similar records in OSTI.GOV collections:

Development of a surface-specific, anti-weathering stone preservative treatment

Conference Rao, S; Brinkar, C; Rao, S; ...

We are testing an anti-weathering preservation strategy that is specific to limestone surfaces. The strategy involves the application of a mineral-specific, bifunctional, passivating/coupling agent that binds to both the limestone surface and to the consolidating inorganic polymer matrix. The sol-gel based reactions form composite materials with desirable conservation and anti-weathering properties. We present the results of our efforts, the highlights of which are: (1) scanning probe microscopy of moisture-free calcite crystals treated with the trisilanol form of silylalkylaminocarboxylate (SAAC), reveals porous agglomerates that offer no significant resistance to the mild leaching action of deionized water. When the crystals are furthermore »« less
Full Text Available
Protective coatings for concrete

Technical Report NAGY, KATHRYN; CYGAN, RANDALL; BRINKER, C; ...

The new two-layer protective coating developed for monuments constructed of limestone or marble was applied to highway cement and to tobermorite, a component of cement, and tested in batch dissolution tests. The goal was to determine the suitability of the protective coating in retarding the weathering rate of concrete construction. The two-layer coating consists of an inner layer of aminoethylaminopropylsilane (AEAPS) applied as a 25% solution in methanol and an outer layer of A2** sol-gel. In previous work, this product when applied to calcite powders, had resulted in a lowering of the rate of dissolution by a factor of tenmore »« less
https://doi.org/10.2172/756038

Full Text Available
Sol-gel preservation of mankind`s cultural heritage in objects constructed of stone

Technical Report Brinker, C; Ashley, C; Sellinger, A

Monuments, buildings, and works of art constructed of carbonate-based stone (calcite, e.g., limestone and marble) are subject to deterioration resulting from the effects of environmental exposure, granular disintegration, freeze/thaw cycles, and salt recrystallization. This damage can potentially be reversed by the use of mineral-specific chemical passivants and consolidants that prevent hydrolytic attack and mechanical weakening. The treatment strategy combined the use of calcite coupling molecules to passivate the surfaces against new weathering with alkoxysilane strengthening or consolidating layers to arrest physical deterioration. The authors report on the effectiveness of passivating agents designed through a combined approach of modeling their adhesivemore »« less
https://doi.org/10.2172/573146

Full Text Available
Sediment alkalinity production in calcite-treated acidic lakes

Miscellaneous Rhea, J

Lake neutralization by the addition of calcite is one form of mitigation currently used to restore lakes acidified by acid deposition. This study focuses on the role that sediments play in reacidification of calcite treated acidic lakes. The study evaluated the effectiveness of sediment treatment in providing acid neutralization capacity (ANC) to the water column of calcite treated lakes during reacidification, determined sediment Ca{sup +2}-H{sup +} exchange coefficients, and evaluated the rate and extent of calcite dissolution and deactivation within lake sediments. The results obtained from these studies were integrated into a mathematical model (SAM) that simulates alkalinity flux frommore »« less
Chemistry and kinetics of calcite dissolution in passive treatment systems

Conference Rose, A

Reaction of calcite with AMD is a key remediation process in anoxic limestone drains, (ALD), SAPS, and many wetlands, but predictions of effluent quality are currently based mainly on rules of thumb and prior experience. The PHREEQC computer program can be used to calculate the progress of this and similar reactions, and aid in understanding, design and evaluation of these systems. At pH values less than 5, calcite dissolution rates are strongly influenced by transport parameters such as flow velocity. Estimated calcite dissolution rates from ALD's and column experiments indicate little change in rate with pH, in contrast to publishedmore »« less

Similar Records