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Title: Inhibition of Aluminum Oxyhydroxide Precipitation with Citric Acid

Abstract

Citric acid has been shown to act as an agent for increasing the solubility of aluminum oxyhydroxides in aqueous solutions of high (>2.47 mol/mol) hydroxide-to-aluminum ratios. Conversely, citric acid also colloidally stabilizes particles in aqueous suspensions of aluminum-containing particles. Solutions of aluminum chloride, with and without citric acid added, were titrated with NaO(aq). The presence and size of particles were determined using quasi-elastic light scattering. In solutions that contained no citric acid, particles formed instantaneously when NaOH(aq) was added but these were observed to rapidly diminish in size, disappearing at OH/Al ratios below 2.5 mol/mol. When the OH/Al ratio was raised beyond 2.5 by addingmoreNaOH(aq), suspensions of colloidally stable particles formed. Large polycations containing 13 aluminum atoms were detected by 27Al solution NMR in citric-acid-free solutions with OH/Al ratios slightly lower than 2.5. In comparison, adding citric acid to solutions of aluminum chloride inhibited the formation of large aluminum-containing polycations. The absence of the polycations prevents or retards the subsequent formation of particles, indicating that the polycations, when present, act as seeds to the formation of new particles. Particles did not form in solutions with a citric acid/aluminum ratio of 0.8 until sufficient NaOH(aq) was added to raise the OH/Almore » ratio to 3.29. By comparison, lower amounts of citric acid did not prevent particles from forming but did retard the rate of growth.« less

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
876999
Report Number(s):
PNNL-SA-47921
Journal ID: ISSN 0743-7463; LANGD5; KC0201050; TRN: US200608%%236
DOE Contract Number:
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Langmuir, 21(25):11690-11695; Journal Volume: 21; Journal Issue: 25
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ALUMINIUM HYDROXIDES; CITRIC ACID; PRECIPITATION; SOLUBILITY; COLLOIDS

Citation Formats

Dabbs, Daniel M., Ramachandran, Usha, Lu, Sang, Liu, Jun, Wang, Li Q., and Aksay, Ilhan A. Inhibition of Aluminum Oxyhydroxide Precipitation with Citric Acid. United States: N. p., 2005. Web. doi:10.1021/la050822f.
Dabbs, Daniel M., Ramachandran, Usha, Lu, Sang, Liu, Jun, Wang, Li Q., & Aksay, Ilhan A. Inhibition of Aluminum Oxyhydroxide Precipitation with Citric Acid. United States. doi:10.1021/la050822f.
Dabbs, Daniel M., Ramachandran, Usha, Lu, Sang, Liu, Jun, Wang, Li Q., and Aksay, Ilhan A. Tue . "Inhibition of Aluminum Oxyhydroxide Precipitation with Citric Acid". United States. doi:10.1021/la050822f.
@article{osti_876999,
title = {Inhibition of Aluminum Oxyhydroxide Precipitation with Citric Acid},
author = {Dabbs, Daniel M. and Ramachandran, Usha and Lu, Sang and Liu, Jun and Wang, Li Q. and Aksay, Ilhan A.},
abstractNote = {Citric acid has been shown to act as an agent for increasing the solubility of aluminum oxyhydroxides in aqueous solutions of high (>2.47 mol/mol) hydroxide-to-aluminum ratios. Conversely, citric acid also colloidally stabilizes particles in aqueous suspensions of aluminum-containing particles. Solutions of aluminum chloride, with and without citric acid added, were titrated with NaO(aq). The presence and size of particles were determined using quasi-elastic light scattering. In solutions that contained no citric acid, particles formed instantaneously when NaOH(aq) was added but these were observed to rapidly diminish in size, disappearing at OH/Al ratios below 2.5 mol/mol. When the OH/Al ratio was raised beyond 2.5 by addingmoreNaOH(aq), suspensions of colloidally stable particles formed. Large polycations containing 13 aluminum atoms were detected by 27Al solution NMR in citric-acid-free solutions with OH/Al ratios slightly lower than 2.5. In comparison, adding citric acid to solutions of aluminum chloride inhibited the formation of large aluminum-containing polycations. The absence of the polycations prevents or retards the subsequent formation of particles, indicating that the polycations, when present, act as seeds to the formation of new particles. Particles did not form in solutions with a citric acid/aluminum ratio of 0.8 until sufficient NaOH(aq) was added to raise the OH/Al ratio to 3.29. By comparison, lower amounts of citric acid did not prevent particles from forming but did retard the rate of growth.},
doi = {10.1021/la050822f},
journal = {Langmuir, 21(25):11690-11695},
number = 25,
volume = 21,
place = {United States},
year = {Tue Dec 06 00:00:00 EST 2005},
month = {Tue Dec 06 00:00:00 EST 2005}
}