Calcite crystal growth inhibition by humic substances with emphasis on hydrophobic acids from the Florida Everglades

Geochimica et Cosmochimica Acta
By: , and 

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Abstract

The crystallization of calcium carbonate minerals plays an integral role in the water chemistry of terrestrial ecosystems. Humic substances, which are ubiquitous in natural waters, have been shown to reduce or inhibit calcite crystal growth in experiments. The purpose of this study is to quantify and understand the kinetic effects of hydrophobic organic acids isolated from the Florida Everglades and a fulvic acid from Lake Fryxell, Antarctica, on the crystal growth of calcite (CaCO3). Highly reproducible calcite growth experiments were performed in a sealed reactor at constant pH, temperature, supersaturation (Ω = 4.5), PCO2(10−3.5atm), and ionic strength (0.1 M) with various concentrations of organic acids. Higher plant-derived aquatic hydrophobic acids from the Everglades were more effective growth inhibitors than microbially derived fulvic acid from Lake Fryxell. Organic acid aromaticity correlated strongly with growth inhibition. Molecular weight and heteroatom content correlated well with growth inhibition, whereas carboxyl content and aliphatic nature did not.

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Publication type Article
Publication Subtype Journal Article
Title Calcite crystal growth inhibition by humic substances with emphasis on hydrophobic acids from the Florida Everglades
Series title Geochimica et Cosmochimica Acta
DOI 10.1016/S0016-7037(99)00179-9
Volume 64
Issue 1
Year Published 2000
Language English
Publisher Elsevier
Contributing office(s) Toxic Substances Hydrology Program
Description 12 p.
First page 61
Last page 72
Country United States
State Florida
Other Geospatial Everglades
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