Reduction of low molecular weight halocarbons in the vapor phase above concentrated humic acid solutions

1984 ◽  
Vol 18 (11) ◽  
pp. 890-893 ◽  
Author(s):  
Jill I. Callaway ◽  
Kasi V. Gabbita ◽  
Vincent L. Vilker
Keyword(s):  
Molecular Weight ◽  
Humic Acid ◽  
Vapor Phase ◽  
Low Molecular Weight ◽  
Acid Solutions

scholarly journals Visualization and Quantification of the Impact of Humic Acid on Zinc Accumulation in Aquatic Plants Using a Low-Molecular-Weight Fluorescent Probe

2021 ◽  
Vol 19 (2) ◽  
pp. 49-63
Author(s):  
Thenuwara Arachchige Omila Kasun Meetiyagoda ◽  
Kabul Fadilah ◽  
Masayori Hagimori ◽  
Mudalige Don Hiranya Jayasanka Senavirathna ◽  
Takeshi Fujino
Keyword(s):  
Molecular Weight ◽  
Humic Acid ◽  
Fluorescent Probe ◽  
Aquatic Plants ◽  
Low Molecular Weight ◽  
Zinc Accumulation ◽  
The Impact

scholarly journals Dissolution of mimetite Pb5(AsO4)3Cl in malic acid solutions

Mineralogia ◽  
2015 ◽  
Vol 45 (1-2) ◽  
pp. 3-12 ◽  
Author(s):  
Piotr Turek ◽  
Tomasz Bajda ◽  
Maciej Manecki
Keyword(s):  
Molecular Weight ◽  
Malic Acid ◽  
Equilibrium Solution ◽  
Solubility Product ◽  
Low Ph ◽  
Organic Ligands ◽  
Low Molecular Weight ◽  
Acid Solutions ◽  
Lead Arsenate ◽  
Organic Solutions

Abstract Mimetite Pb5(AsO4)3Cl is the most insoluble lead arsenate mineral and could be used in remediation techniques to reduce As(V) mobility in soils. However, low-molecular-weight organic acids such as malic acid increase its solubility. The effect of malic acid on the dissolution of mimetite strongly depends on the pH of the equilibrium solution. At low pH, mimetite is decomposed mostly by the mechanism of protonation. With increasing pH, the solubility of mimetite decreases and a greater influence in its dissolution is ascribed to complexation of Pb(II) by organic ligands. During dissolution experiments, the amount of arsenic released to solution was > 26% higher in organic solutions than in inorganic solutions, and the amount of lead was > 8% greater. The solubility product of mimetite (KSP) was calculated in order to quantify the thermodynamic stability of the investigated mineral. The value obtained, i.e., -24.52 ± 0.49 fluctuates between the values of -21.69 ± 1.05 and -27.87 ± 0.42 reported in the literature.

scholarly journals REDUCTION AND OXIDATION PROCESSES OF CHROMIUM IN HUMIC ACID SUBFRACTION-SENSITIZED PHOTOCATALYST

2010 ◽  
Vol 4 (3) ◽  
pp. 168-173
Author(s):  
Uripto Trisno Santoso ◽  
Herdiansyah Herdiansyah ◽  
Sri Juari Santosa ◽  
Dwi Siswanta
Keyword(s):  
Molecular Weight ◽  
Humic Acid ◽  
High Molecular Weight ◽  
Peat Soil ◽  
Low Molecular Weight ◽  
Oxidation Processes ◽  
Weight One ◽  
Centrifugation Method ◽  
Reduction And Oxidation ◽  
Uv Lamps

The process of reduction and oxidation of soluble chromium in humic acid subfraction-sensitized photocatalyst was studied. Humic acid was extracted from peat soil sampled in Gambut District, South Kalimantan. Humic acid (HA) was fractionated to humic acid subfraction (HAS) by centrifugation method. ZnO and TiO2 were applied as the photocatalysts produced by Merck, suspended in solution of 2 g/L. Two germicide UV lamps 30 watt (Philip®) was placed in a box at 20 cm above the samples. The results showed that HA or HAS sensitized the photoreduction of Cr(VI) by photocatalyst. The low molecular weight of HAS is more effective to act as sensitizer than the high molecular weight one. The yield of the photoreduction of Cr(VI) with photocatalysts enhanced both in the presence of Fe(II) ion and HAS. UV irradiation of the MnO4- solutions containing Cr(III) induced the photooxidation of Cr(III) to Cr(VI). The presence of Fe(III) or HAS doesn't inhibit significantly. The inhibition is enhanced by the present of both HAS and Fe(II) or HAS and Fe(III). This inhibition is enhanced more by the presence of ZnO or TiO2 photocalysts.   Keywords: reduction, oxidation, chromium, humic acid, photocatalyst

AN EXAMINATION OF THE HUMIC ACIDS OF SPHAGNUM PEAT

1964 ◽  
Vol 44 (1) ◽  
pp. 76-87 ◽  
Author(s):  
D. G. Smith ◽  
J. W. Lorimer
Keyword(s):  
Molecular Weight ◽  
Humic Acid ◽  
Sodium Hydroxide ◽  
Humic Acids ◽  
Infrared Spectra ◽  
Low Molecular Weight ◽  
Salt Solutions ◽  
Similar Composition ◽  
Sphagnum Peat ◽  
Dilute Sodium Hydroxide

Humic acid fractions were prepared by the repeated extraction of Sphagnum peat with dilute sodium hydroxide. The infrared spectra of the initial fractions were typical of humic acids. Spectra of the later fractions were indicative of an aromatic structure similar to that of lignin. The content of methoxyl groups, which had remained constant through the earlier fractions, increased rapidly in the later fractions. Changes in the intrinsic viscosity of the fractions in aqueous alkali and salt solutions paralleled those observed in the infrared spectra and methoxyl group content. The results show that humic acids of similar composition and increasing molecular weight were extracted initially, and that low molecular weight material resembling lignin predominated towards the end of the extraction. The presence of lignin was confirmed by alkaline nitrobenzene oxidation of a peat residue. Dilute sodium pyrophosphate extracted humic acids which were similar in all respects to the first fraction obtained by extraction with dilute sodium hydroxide.

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