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Surface complexation of carboxylate adheres Cryptosporidium parvum öocysts to the hematite-water interface

Environmental Science & Technology

By:
, , , , and
https://doi.org/10.1021/es901346z

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Abstract

The interaction of viable Cryptosporidium parvum öocysts at the hematite (α-Fe2O3)−water interface was examined over a wide range in solution chemistry using in situ attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. Spectra for hematite-sorbed öocysts showed distinct changes in carboxylate group vibrations relative to spectra obtained in the absence of hematite, indicative of direct chemical bonding between carboxylate groups and Fe metal centers of the hematite surface. The data also indicate that complexation modes vary with solution chemistry. In NaCl solution, öocysts are bound to hematite via monodentate and binuclear bidentate complexes. The former predominates at low pH, whereas the latter becomes increasingly prevalent with increasing pH. In a CaCl2 solution, only binuclear bidentate complexes are observed. When solution pH is above the point of zero net proton charge (PZNPC) of hematite, öocyst surface carboxylate groups are bound to the mineral surface via outer-sphere complexes in both electrolyte solutions.

Additional publication details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Surface complexation of carboxylate adheres Cryptosporidium parvum öocysts to the hematite-water interface
Series title:
Environmental Science & Technology
DOI:
10.1021/es901346z
Volume:
43
Issue:
19
Year Published:
2009
Language:
English
Publisher:
American Chemical Society
Contributing office(s):
National Research Program - Central Branch
First page:
7423
Last page:
7429