X-ray diffraction studies on the crystallinity and molecular weight of humic acids

Visser, S. A.; Mendel, H.

doi:10.1016/0038-0717(71)90022-8

Cited by 13 publications

(3 citation statements)

References 12 publications

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“…) exhibits very small diffuse peaks with a few intense peaks, implying its non‐crystalline nature. This behavior is consistent with the behavior observed in the case of humic substances from other sources . The weaker diffraction lines of HASIL exhibit the humic particles are coated with ILs.…”

Section: Resultssupporting

confidence: 89%

Microwave Synthesis of Fused Pyrans by Humic Acid Supported Ionic Liquid Catalyst and Their Antimicrobial, Antioxidant, Toxicity Assessment, and Molecular Docking Studies

Thangaraj

Ranjan

Ramesh

et al. 2019

Journal of Heterocyclic Chem

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A series of fused quinolinyl and quinolonyl pyrans were synthesized via a one‐pot reaction of quinolinyl and quinolonyl carbaldehydes, malononitrile, and a 1,3‐diketone. The reactions were catalyzed by a new humic acid supported 1‐butyl‐3‐methyl imidazolium thiocyanate ionic liquid under microwave irradiation conditions. Antimicrobial, antioxidant, and toxicity studies displayed various biological activities depending on structure of the pyrans.

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Section: Resultssupporting

confidence: 89%

Microwave Synthesis of Fused Pyrans by Humic Acid Supported Ionic Liquid Catalyst and Their Antimicrobial, Antioxidant, Toxicity Assessment, and Molecular Docking Studies

Thangaraj

Ranjan

Ramesh

et al. 2019

Journal of Heterocyclic Chem

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“…1976). The controversy over the moleeular weight of the dissolved humic matter can undoubtedly be explained in part by the different origins of the materials investigated, but also by the different and often unreliable methods used for estimating molecular weight (Visser & Mendel, 1971: Cameron ci al., 1972: Kemp & Wong, 1974Wershaw. Pinckney & Booker.…”

Section: Introductionmentioning

confidence: 99%

Seasonal changes in the concentration and colour of humic substances in some aquatic environments

Visser

1984

Freshwater Biology

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SUMMARY. 1. Between February and September 1974, concentrations of fulvic and humic acids in waters from a cryoboreal region of the Precambrian Shield in Quebec varied between 0.5–6.1 mg 1−1 and 0.1–6.5 mg 1−1 respectively. Whereas the fulvic acids usually remained relatively constant during this period, humic acids showed appreciable increases. 2. The number and weight average molecular weights of the fulvic acids (∼5000 and ∼22,000 daltons respectively) were lower than those of the humic acids (∼20,000 and ∼75,000 daltons respectively). The average molecular weight of the aquatic humic matter often decreased during late summer and early autumn. During spring floods the molecular weight of fulvic acids increased and that of humic acids declined. 3. Because the aquatic humic acids were more intensely coloured than fulvic acids, they contributed more than 30% of the colour of the water even though they accounted for only 15% of the concentration of humic matter. The colour intensity of both fulvic and humic acids generally appeared to increase during the latter part of the summer, when there was normally a decrease in the value of the colour quotient (E4/E6 ratio), indicating the accumulation in the waters of more humified material.

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“…This behaviour is consistent with the behaviour observed in the case of humic substances from other sources. 23,24 Differential scanning calorimetry (DSC)…”

Section: X-ray Diffraction Patternmentioning

confidence: 99%

Humic acid from Shilajit: A physico-chemical and spectroscopic characterization

Agarwal¹,

Anwer²,

Khanna³

et al. 2010

J. Serb. Chem. Soc.

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Shilajit is a blackish-brown exudation, consisting of organic substances, metal ions and minerals, from different formations, commonly found in the Himalayan region (1000-3000 m) from Nepal to Kashmir. Shilajit can also b e collected t hroughout the mountain region s i n Afghani stan, Bhutan, China, Bajkal, throughout Ural, Cauc asus and Altai mountains also, at altitudes between 1 000 to 5000 m. The major phy siological acti on of shilaj it has be en attributed to t he presence of b ioactive dibenzo-α-pyrones together with humic and fulvic acid s, which act as carrier molecu les for the active ingredient s. In this work, the aim was to extract humic acid from Shilajit from various sources and characterised these humic acids based on their physicochemical properties, elemental analysis, UV/Vis and FTIR spectra, X-ray diffraction pattern and DSC thermograms. The spectral fea tures obtaine d fro m UV/Vi s, FTIR, XRD an d DSC studies for sa mples of different origins sh owed a distinct similarity amongst the mselves and i n c omparison to soil hu mic acids. The surfacta nt properties of th e extract ed ful vic acid s were investigated by deter mining th e effect of increa sing c oncentration on the surf ace ten sion of water. The stu dy demonstrated t hat hu mic a cids extra cted from shilajit inde ed po ssessed surfactant properties.

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X-ray diffraction studies on the crystallinity and molecular weight of humic acids

Cited by 13 publications

References 12 publications

Microwave Synthesis of Fused Pyrans by Humic Acid Supported Ionic Liquid Catalyst and Their Antimicrobial, Antioxidant, Toxicity Assessment, and Molecular Docking Studies

Microwave Synthesis of Fused Pyrans by Humic Acid Supported Ionic Liquid Catalyst and Their Antimicrobial, Antioxidant, Toxicity Assessment, and Molecular Docking Studies

Seasonal changes in the concentration and colour of humic substances in some aquatic environments

Humic acid from Shilajit: A physico-chemical and spectroscopic characterization

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