Pa Ho Hsu

Rutgers, The State University of New Jersey

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D. A. Rennie

University of Saskatchewan

Ming K. Wang

Rutgers, The State University of New Jersey

Ping Ping Tsai

Industrial Technology Research Institute

F. J. Sikora

University of Kentucky

Ming K. Wang

National Taiwan University

H. van Olphen

Rutgers Sexual and Reproductive Health and Rights

F. Fiessinger

Association pour l'Utilisation du Rein Artificiel dans la région Lyonnaise

Dianxue Cao

Harbin Engineering University

Ping‐Ping Tsai

Weizi Wang

Fudan University

Cooperative Institutions

Rutgers, The State University of New Jersey

Rutgers Sexual and Reproductive Health and Rights

University of Kentucky

University of Illinois Urbana-Champaign

The Ohio State University

Purdue University West Lafayette

Association pour l'Utilisation du Rein Artificiel dans la région Lyonnaise

Texas A&M University

National Cheng Kung University

ITRI International

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Formation of Gibbsite from Aging Hydroxy‐Aluminum Solutions

Soil Science Society of America Journal (1966)

Pa Ho Hsu

Abstract Hydroxy‐aluminum solutions of NaOH/AlCl 3 molar ratio = 0.3 to 2.7 and concentration of Al = 0.02 m were prepared and aged for 2 years. The solutions of NaOH/AlCl 3 = 1.5 and below remained unchanged during the entire period of study. Those solutions of NaOH/AlCl 2 molar ratio = 1.8 to 2.7 were stable for about 6 months to 1 year, then the solutions gradually became turbid, and eventually gibbsite formed in association with a decrease in pH. When a solution of NaOH/AlCl 3 = 2.7 was either diluted ten‐fold with water or dialyzed to remove the Na + and Cl ‐ , the same reaction took place in 2 weeks. When NaCl was added at a concentration of 0.12 m , the solution became only slightly turbid at the end of 1 year. At 0.6 and 1.2 m NaCl, amorphous Al precipitates formed immediately after preparation and remained amorphous even after 2 years. It is proposed that the formation of gibbsite from aging hydroxy‐aluminum solutions follows the same mechanism as the rapid precipitation of bayerite at NaOH/AlCl 3 = 3 in an alkaline medium, the latter being discussed previously by Hsu and Bates in 1964. The difference between these two processes is the source of OH ‐ for the completion of neutralization. The OH ‐ added as NaOH is taken up by hydroxy‐aluminum polymers almost instantaneously, whereas the spontaneous hydrolysis of these polymers is slow, particularly in the presence of high salt concentration.

Gibbsite

Metaphosphate

Molar ratio

10.2136/sssaj1966.03615995003000020011x

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Citations (59)

Mechanisms of Gibbsite Crystallization from Partially Neutralized Aluminum Chloride Solutions

Clays and Clay Minerals (1988)

Pa Ho Hsu

Gibbsite

Alkalinity

10.1346/ccmn.1988.0360104

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Citations (43)

Effect of Temperature on the Degradation of Al13 Complex

Clays and Clay Minerals (1997)

Pa Ho Hsu

Degradation

10.1346/ccmn.1997.0450216

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Citations (15)

The Nature of Polynuclear OH-Al Complexes in Laboratory-Hydrolyzed and Commercial Hydroxyaluminum Solutions1

Clays and Clay Minerals (1994)

Weizi Wang Pa Ho Hsu

Gibbsite

Dilution

10.1346/ccmn.1994.0420313

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Citations (62)

Determination of Iron with Thiocyanate

Soil Science Society of America Journal (1967)

Pa Ho Hsu

Abstract The effects of acidity and concentration of thiocyanate on the intensity and stability of the iron‐thiocyanate color solution were studied in detail, and a procedure was proposed. In the proposed procedure, a combination of 3 ml of 6 N HCl and 10 ml of 20% KSCN is recommended. In the presence of this amount of KSCN, the color intensity was constant while the amount of HCl varied from 5 to 30 meq. Hydroxy‐iron polymers in the sample solution can be decomposed by heating the aliquot in the presence of acid prior to the addition of KSCN. By adding H 2 O 2 at the end of the procedure, it is possible to confine the reading time within a short interval and thus overcome rapid color fading.

Thiocyanate

Intensity

10.2136/sssaj1967.03615995003100030020x

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Citations (8)

Reaction of OH-Al Polymers with Smectites and Vermiculites1

Clays and Clay Minerals (1992)

Pa Ho Hsu

Hectorite

Depolymerization

10.1346/ccmn.1992.0400308

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Citations (35)

Aluminum Fixation in a Synthetic Cation Exchanger

Soil Science Society of America Journal (1960)

Pa Ho Hsu C. I. Rich

Abstract Previous studies of soils have indicated fixation of Al as a poistively charged ion or polymer by some clay minerals. To avoid reactions with structural Al in clays, a synthetic cation‐exchange resin, Dowex‐50, was employed in a preliminary study of Al fixation. This resin was Al‐saturated and then serially titrated with NaOH. In a similar experiment, AlCl 3 was added in an amount equivalent to the Al in the resin, prior to titration. In a third experiment the same amount of Al‐saturated resin was added to different volumes of solutions containing NaOH and AlCl 3 in molar ratios of 0.296, 1.185, and 2.37, respectively. All of these experiments indicate that the only exchangeable Al ion was Al 3+ and that in the acid range nonexchangeable Al was fixed so that on the average one positive charge of the resin was countered by one Al ion. A gibbsite‐like ring structure having 6 Al ions, 12 OH ions and 12 water molecules is proposed as the principal fixed hydroxy‐Al polymer. The polymer may be formed in place from smaller chain‐like polymers and fixed because of its large size and high charge.

Gibbsite

Ion-exchange resin

Cation-exchange capacity

10.2136/sssaj1960.03615995002400010015x

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Citations (54)

EFFECT OF SALTS ON THE FORMATION OF BAYERITE VERSUS PSEUDO-BOEHMITE

Soil Science (1967)

Pa Ho Hsu

Boehmite

10.1097/00010694-196702000-00003

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Citations (53)

27Al Nuclear Magnetic Resonance and Ferron Kinetic Studies of Partially Neutralized AlCl3 Solutions1

Clays and Clay Minerals (1986)

Dorothy Z. Denney Pa Ho Hsu

10.1346/ccmn.1986.0340516

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Citations (23)

Fixation of Hydroxy‐Aluminum Polymers by Vermiculite

Soil Science Society of America Journal (1964)

Pa Ho Hsu T. F. Bates

Abstract The addition of vermiculite to hydroxy‐aluminum (OH‐Al) solutions prepared by the controlled addition of NaOH to AlCl 3 results in the fixation of OH‐Al polymers by the clay. With solutions of NaOH/Al molar ratios = 0.3 to 2.1, the polymers held by the clay are of nearly constant composition, very close to the formula [Al 6 (OH) 12 ] 6+ (single ring) or [Al 10 (OH) 22 ] 8+ (double ring). The polymers are present in a single layer in the interlayer space. All specimens give a strong 14Å. X‐ray diffraction peak of similar intensity on K + saturation even though the proportion of cation‐exchange positions occupied by the OH‐Al polymers varies from 24% to 61% on an equivalent basis. With solutions of NaOH/Al = 2.25 to 2.70, the polymers held by clay gradually increase in size and decrease in net positive charge per Al atom with increasing NaOH/Al ratio. The polymers are also present in a single layer in the interlayer space, but it takes more Al atoms and a longer time for the polymers in this group to produce a 14Å. peak of an intensity corresponding to that obtained when the Al is in the form of single or double ring units. In those specimens in which the amount of Al fixed is not sufficient to hold the vermiculite layer apart effectively, the Al polymer‐vermiculite layer is randomly interstratified with K‐vermiculite, and the resultant X‐ray diffraction patterns vary widely, some appearing as though X‐ray amorphous components were present. For all of the above mentioned specimens, no noticeable change has been found in the composition of the polymers held by clay minerals during aging up to 6 months. No crystalline Al(OH) 3 was detected in any of these specimens. It is concluded that vermiculite functions as an anion which has a strong affinity for OH‐Al polymers and which inhibits the formation of gibbsite in soils. At NaOH/Al = 3, no OH‐Al polymer is found in the interlayer space but crystalline Al(OH) 3 forms outside the clay lattice within two weeks.

Vermiculite

Saturation (graph theory)

10.2136/sssaj1964.03615995002800060025x

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Citations (73)