Mandelic acid and phenyllactic acid “Reaction Sets” for exploring the kinetics and mechanism of oxidations by hydrous manganese oxide (HMO)

Two hydroxy acids reaction sets are used to explore the kinetics, the role of physicochemical properties, and medium effects of the heterogeneous reactions on hydrous manganese oxide (HMO) surface.

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The role of Mn2+-rich hydrous manganese oxide in the accumulation of arsenic in lake sediments

Water Research ◽

10.1016/0043-1354(85)90372-0 ◽

1985 ◽

Vol 19 (8) ◽

pp. 1029-1032 ◽

Cited By ~ 93

Author(s):

T. Takamatsu ◽

M. Kawashima ◽

M. Koyama

Keyword(s):

Manganese Oxide ◽

Lake Sediments ◽

Hydrous Manganese Oxide

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Mechanism of Oxidative Decarboxylation of α-Hydroxy Acids by Bromine Water. Part II. Oxidation in Acidic Medium. A Comparison with the HOBr – Oxalic Acid Reaction

Canadian Journal of Chemistry ◽

10.1139/v71-105 ◽

1971 ◽

Vol 49 (4) ◽

pp. 654-659 ◽

Cited By ~ 3

Author(s):

Judith M. Pink ◽

Ross Stewart

Keyword(s):

Steady State ◽

Oxalic Acid ◽

Acidic Medium ◽

Mandelic Acid ◽

Reaction Path ◽

Oxidative Decarboxylation ◽

Hydroxy Acids ◽

Bromine Water ◽

Acid Reaction ◽

Ph Range

The oxidative pattern of α-hydroxy acids by acidic bromine water is shown to be similar to the oxalic acid – bromine water reaction. In both cases HOBr is the oxidant and the undissociated form of the organic acid is required for reaction to occur. The rate law −d[HOBr]/dt = k[HOBr][hydroxy acid] is observed for oxidations carried out in the presence of Ag+ ion in the pH range 2–5. Below that pH bromination occurs. Bell-shaped pH-rate profiles are obtained for the oxidations of benzilic, mandelic, and 2-hydroxy-2-methylpropanoic acids. The calculated rates, based on a steady state treatment of a reaction path involving a hypobromite intermediate (R2COBrCO2H) are in agreement with the observed values and with the observation that the rates of oxidation of mandelic acid in D2O and H2O are the same.

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Characteristics Of The Structure Formation Of Gypsum Binder Modified With Zinc Hydrosilicates

Promyshlennoe i Grazhdanskoe Stroitel stvo ◽

10.33622/0869-7019.2020.02.40-46 ◽

2020 ◽

pp. 40-46

Keyword(s):

Synergistic Effect ◽

Physicochemical Properties ◽

Structure Formation ◽

Silicic Acid ◽

Chemical Properties ◽

Crystal Formation ◽

Ability To Act ◽

Chemical Factors ◽

Sorption Characteristics

The authors' methodic for assessing the role of chemical and physic-chemical factors during the structure formation of gypsum stone is presented in the article. The methodic is also makes it possible to reveal the synergistic effect and to determine the ranges of variation of controls factors that ensure maximum values of such effect. The effect of a micro-sized modifier based on zinc hydro-silicates on the structure formation of building gypsum is analyzed and corresponding dependencies are found. It is shown that effects of influence of modifier on the properties of gypsum compositions are determined by chemical properties of modifier. Among the mentioned properties are sorption characteristics (which depend on the amount of silicic acid and its state) and physicochemical properties - the ability to act as a substrate during crystal formation. The proposed method can also be extended to other binding substances and materials. This article contributes to the understanding of the processes that occur during the structure formation of composites, which will make it possible to control the structure formation in the future, obtaining materials with a given set of properties.

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Novel adsorptive membrane through embedding thiol-functionalized hydrous manganese oxide into PVC electrospun nanofiber for dynamic removal of Cu(II) and Ni(II) ions from aqueous solution

Journal of Water Process Engineering ◽

10.1016/j.jwpe.2020.101401 ◽

2020 ◽

Vol 37 ◽

pp. 101401

Author(s):

M. Hezarjaribi ◽

Gh. Bakeri ◽

M. Sillanpää ◽

M.J. Chaichi ◽

S. Akbari

Keyword(s):

Aqueous Solution ◽

Manganese Oxide ◽

Electrospun Nanofiber ◽

Hydrous Manganese Oxide ◽

Adsorptive Membrane

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The Role of H2C2O4 and Na2CO3 as Precipitating Agents on The Physichochemical Properties and Photocatalytic Activity of Bismuth Oxide

Open Chemistry ◽

10.1515/chem-2020-0013 ◽

2020 ◽

Vol 18 (1) ◽

pp. 129-137

Author(s):

Yayuk Astuti ◽

Rizka Andianingrum ◽

Abdul Haris ◽

Adi Darmawan ◽

Keyword(s):

Photocatalytic Activity ◽

Methyl Orange ◽

Physicochemical Properties ◽

Bismuth Oxide ◽

Rate Constants ◽

Degradation Rate ◽

Precipitation Method ◽

Methyl Orange Degradation ◽

Methyl Orange Dye

AbstractSynthesis of bismuth oxide synthesis through the precipitation method using H2C2O4 and Na2CO3 precipitating agents, identification of physicochemical properties and its photocatalysis activity for methyl orange degradation were conducted. The bismuth oxide synthesis was undertaken by dissolving Bi(NO3)3.5H2O in HNO3, then added precipitating agents to form precipitate. The results showed that bismuth oxide produced by H2C2O4 precipitating agent was a yellow powder containing a mixture of α-Bi2O3 (monoclinic) and β-Bi2O3 (tetragonal), porous with size of 28-85 μm. Meanwhile, the use of Na2CO3 as precipitating agent resulted in bismuth oxide consisting of α-Bi2O3 and β-Bi2O3 and Bi2O4, irregular shape without pore being 40-115 μm in size. Bismuth oxide synthesized with H2C2O4 precipitating agent showed higher photocatalytic activity compared to bismuth oxide synthesized using Na2CO3 on degrading methyl orange dye with degradation rate constants of 2.35x10-5 s-1 for H2C2O4 and 1.81x10-5 s-1 for Na2CO3.

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