Liberation of H+, Al+++ and Fe+++ ions from pure clay minerals on repeated salt treatment and desaturations☆
About: This article is published in Journal of Colloid Science.The article was published on 1948-10-01. It has received 14 citations till now. The article focuses on the topics: Clay minerals & Salt (chemistry).
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TL;DR: In this article, the authors used bacterial activity to produce reducing conditions with kaolinite and halloysite coated with iron oxides and with nontronite in which ferric iron is in the octahedral position within the lattice.
192 citations
TL;DR: One-g samples of a montmorillonite, a metabentonite, an illite, two kaolinites, and three halloysites were treated with 50 ml of hydrochloric acid (6·45 N 1: 1), acetic acid (4·5 N, 1: 3), sodium hydroxide (2·8N), sodium chloride solution (pH 6·10; Na = 35‰; Cl = 21·5
Abstract: One-g samples of a montmorillonite, a metabentonite, an illite, two kaolinites, and three halloysites were treated with 50 ml of hydrochloric acid (6·45 N, 1: 1), acetic acid (4·5 N, 1: 3), sodium hydroxide (2·8N), sodium chloride solution (pH 6·10; Na = 35‰; Cl = 21·5‰), and natural sea water (pH 7·85; Na = 35·5‰; Cl = 21·5‰) for a 10-day period in stoppered plastic vials. The supernatant solutions were removed from the clay minerals and analyzed for SiO2, Al2O3, CaO, MgO, Na2O, and K2O. All the solutions removed some SiO2, Al2O3, and Fe2O3 from the samples, but the quantities were small. Sodium hydroxide attacked the kaolin group minerals more strongly than it did montmorillonite, metabentonite, or illite. Halloysite was more strongly attacked by hydrochloric acid than was any of the other experimental minerals. Hydrochloric acid removed iron oxide coatings from soil clay minerals, but acetic acid did not remove them completely. The samples most strongly attacked by HCl and NaOH were examined by X-ray diffraction. Acid treatment did not destroy the structure of the clays, but the halloysite structure was partially destroyed. Sodium hydroxide attacked the halloysite structure, as shown by chemical analysis and X-ray diffraction. These experiments show that treatment in dilute acids has no harmful effect in the preparation of clays for X-ray diffraction. Acetic acid is preferred to hydrochloric acid for this purpose. Hydrochloric acid cleans clay minerals by removing free iron oxide from the surface; acetic acid is less effective.
135 citations
112 citations
TL;DR: In this article, the effect of some anions (humic acid ≈ succinate ≈ polystyrenesulfonate) is to decrease phosphate adsorption for pH < 6.
103 citations
TL;DR: The insoluble phosphorus compounds present in soils can be classified as the oxy- and hydroxyphosphates of Fe +3, Fe +2, Al +2, Al +3, Ca+2, Ti +4, Mg +2 and Mn +2 as mentioned in this paper.
Abstract: Publisher Summary Phosphorus fixation was first recognized in Europe around 1850, when it was reported that soil had the ability to “retain” phosphorus. Similar reports appeared in the United States shortly after 1900. However, in spite of this early recognition, the greatest strides in understanding the basic chemistry of this phenomenon and how to cope with it have been made only in the past 25 years. The insoluble phosphorus compounds present in soils can be classed generally as the oxy- and hydroxyphosphates of Fe +3 , Fe +2 , Al +3 , Ca +2 , Ti +4 , Mg +2 , and Mn +2 . The predominant soluble phosphorus ion present in the soil solution is H 2 PO 4 - , and it is generally conceded that this anion is the source of phosphorus used by plants. Organic phosphorus compounds are also fixed in the soil. Certain compounds, notably phytin and its derivatives, form insoluble aluminium, iron, and calcium compounds in a manner similar to orthophosphate. In addition, other compounds possessing basic or cationic characteristics— namely, nucleic acids and their derivatives—are adsorbed by a cation-exchange mechanism.
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01 Sep 1927
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TL;DR: The mechanism of this reaction has been the subject of much discussion as discussed by the authors, and some investigators consider that the acid liberated by the salt dissolves A1+++ and Fe+++ ions from the sesquioxides present in the hydrogen clay, while others postulate a direct exchange of A1+ and Fe+ ions for the cations of the added salt.
Abstract: THE interaction between hydrogen clays and neutral salts gives rise to H+ and A1+++ and, in a secondary measure, Fe+++ ions in the salt extracts. The mechanism of this reaction has been the subject of much discussion1–8. Some investigators1–5 consider that the acid liberated by the salt dissolves A1+++ and Fe+++ ions from the sesquioxides present in the hydrogen clay, while others6–8 postulate a direct exchange of A1+++ and Fe+++ ions for the cations of the added salt.
7 citations