نتایج جستجو برای: humic acids
تعداد نتایج: 268450 فیلتر نتایج به سال:
Humic substances (HS) reportedly enhance moisture retention of soil. However, no information is available as to the effects of HS on sand-based golf course putting greens. HS have acidic functional groups (COOH) that are reaction sites on the molecule. An greenhouse experiment was conducted to evaluate the effect that the acidic functional groups in humic acid, tannic acid and citric acid have ...
Natural organic matter (NOM) in surficial or ground water exists as a variety of molecular sizes and complex mixture of polyfunctional organic compounds. Adsorption of these organic compounds onto inorganic colloids can alter the physicochemical properties of the solid. Although many classical adsorption models have been developed, little consideration has been given to desorption modeling, so ...
Nuclear magnetic resonance (NMR) experiments on carbon-13 in the solid state were done with cross polarization (CP) and magic angle spinning (MAS) in order to overcome the low NMR sensitivity of (13)C and the chemical shift anisotropy, respectively. In the present research, CPMAS (13)C-NMR spectra were collected by modulating the contact time needed for cross polarization (variable contact time...
Deinococcus radiodurans is an exceptionally radiation-resistant microorganism capable of surviving acute exposures to ionizing radiation doses of 15,000 Gy and previously described as having a strictly aerobic respiratory metabolism. Under strict anaerobic conditions, D. radiodurans R1 reduced Fe(III)-nitrilotriacetic acid coupled to the oxidation of lactate to CO(2) and acetate but was unable ...
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 be tween 1 000 to 5000...
Carbon nanotubes have shown great potential as effective adsorbents for hydrophobic organic contaminants in water treatment. The present study investigated the influence of aqueous solution chemistry on the adsorption of tetracycline to carbon nanotubes. Specifically, the effects of ionic strength (NaCl and CaCl(2) ) and presence of Cu(2+) ion (7.5 mg/L) or dissolved soil or coal humic acids (5...
The positive effect of humic acids on the growth of plant roots is well known, however, the mechanisms and role of their physical structure in these processes have not been fully explained yet. In this work, South-Moravian lignite was oxidized by means of nitric acid and hydrogen peroxide to produce a set of regenerated humic acids. The elemental composition, solid state stability and solution ...
The sorption coefficient, K(OC), of phenanthrene (PHE) has been reported to vary with different types of organic matter, leading to uncertainties in predicting the environmental behavior of PHE. Among the studies that relate organic matter properties to their sorption characteristics, physical conformation of organic matter is often neglected. In this work, organic matter samples of different p...
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