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Retention of Arsenic by Hydroxy‐Aluminum on Surfaces of Micaceous Mineral Colloids
Author(s) -
Huang P. M.
Publication year - 1975
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1975.03615995003900020016x
Subject(s) - mica , vermiculite , chemistry , muscovite , mineral , arsenate , adsorption , colloid , biotite , arsenic , inorganic chemistry , nuclear chemistry , mineralogy , metallurgy , materials science , organic chemistry , quartz , composite material
This study was carried out to examine the relative significance of As retention by hydroxy‐Al on external and interlamellar surfaces of micaceous mineral colloids. Depletion of K from muscovite and biotite decreased As retention. This effect was attributed to the exclusion of arsenate ions by the K‐depleted layers. Hydroxy‐Al in the interlamellar spaces of vermiculite and K‐depleted micas was not found to contribute significantly to As retention in the solution concentration range of 2 to 10 ppm As. Changes in solution pH from near neutral to strongly acidic and variable concentrations of NaCl (0, 0.1, 1.0 N ) did not promote As retention by hydroxy‐Al in interlamellar space of the micaceous minerals. Hydroxy‐Al on the external surfaces of micaceous mineral colloids is significant in the retention of As, particularly when particle size is < 0.2µm. As the mica particles decreased in size (2–5, 0.2–2, 0.08–0.2, and < 0.08µm), the Langmuir adsorption maximum of hydroxy‐Al mica complexes for As increased; whereas the bonding energy of the complexes for As decreased. The molar As/Al ratio of mineral surfaces also decreased with decreasing size of mica particles.