Determination of direct and indirect photolysis rates of 2-chlorophenol in humic acid solution and natural waters

Chemosphere ◽  
1992 ◽  
Vol 25 (5) ◽  
pp. 635-641 ◽  
Author(s):  
Hideki Kawaguchi
Keyword(s):  
Humic Acid ◽  
Acid Solution ◽  
Natural Waters ◽  
Indirect Photolysis ◽  
Photolysis Rates

A chemiluminescence study of the kinetics of reactions of Cr(III) with carboxylate ligands: oxalate, salicylate, and humic acid

1990 ◽  
Vol 68 (6) ◽  
pp. 881-885 ◽  
Author(s):  
Douglas L. Huizenga ◽  
Howard H. Patterson
Keyword(s):  
Humic Acid ◽  
Reaction Kinetics ◽  
Rate Constants ◽  
Natural Waters ◽  
Ligand Concentration ◽  
Reaction Pathways ◽  
Carboxylate Ligands ◽  
Kinetics Of ◽  
Insight Into

The reaction of Cr(III) with chelate-forming carboxylate ligands can be monitored at the low ligand concentrations typical of natural waters by chemiluminescence analysis of unreacted Cr(III). This technique is utilized here for the measurement of Cr(III) reaction kinetics with oxalate, salicylate, and humic acid over a wider ligand concentration range than previously reported. Variation of the pH and ligand concentrations allowd the determination of rates of reaction by three pathways with different pH dependencies. The magnitude of rate constants of these pathways for Cr(III) with inorganic (Cl−, SCN−) and carboxylate ligands gives insight into the reaction pathways for the environmentally important ligand humic acid. Keywords: Cr(III), oxalate, salicylate, humic acid.

scholarly journals Simple Electrochemical Determination of Surface-Active Substances in Natural Waters

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Željka Cvrković-Karloci ◽  
Damir Krznarić ◽  
Marijan Šeruga ◽  
Božena Ćosović
Keyword(s):  
Humic Acid ◽  
Natural Waters ◽  
Electrochemical Determination ◽  
Danube River ◽  
Calibration Plot ◽  
Linear Calibration ◽  
Capacitive Current ◽  
Surface Active ◽  
Active Substances

A simple electrochemical determination of surface-active substances by using time-dependent variation of the capacitive current in a.c. voltammetry at the HMDE is described. Surface-active substances were accumulated by stirring solution at the deposition potential of −0.6 V versus Ag/AgCl (sat. NaCl). The capacitive current was recorded for different deposition times in the range 0–120 s, wherefrom the linear calibration plot is constructed. The proposed method was verified for model surfactant TritonX-100 in the concentration range 0.02–0.25 mg/L and for humic acid in the concentration range 1.65–20 mg/L. The application of the method was demonstrated for freshwater samples of the Drava river, Danube river, and the wetland Kopački Rit, Croatia. The shape of theiac-Ecurves as well as the obtained concentrations of surface-active substances by using humic acid as the calibration substance are quite well describing the type and the nature of organic matter in the freshwater samples.

scholarly journals Determination of Organic Compounds, Fulvic Acid, Humic Acid, and Humin in Peat and Sapropel Alkaline Extracts

Molecules ◽  
2021 ◽  
Vol 26 (10) ◽  
pp. 2995
Author(s):  
Laurynas Jarukas ◽  
Liudas Ivanauskas ◽  
Giedre Kasparaviciene ◽  
Juste Baranauskaite ◽  
Mindaugas Marksa ◽  
...  
Keyword(s):  
Humic Acid ◽  
Fulvic Acid ◽  
Humic Substances ◽  
Organic Compounds ◽  
Chemical Constituents ◽  
Acid Amide ◽  
Extraction Methods ◽  
Ultrasound Extraction ◽  
Different Origins

Black, brown, and light peat and sapropel were analyzed as natural sources of organic and humic substances. These specific substances are applicable in industry, agriculture, the environment, and biomedicine with well-known and novel approaches. Analysis of the organic compounds fulvic acid, humic acid, and humin in different peat and sapropel extracts from Lithuania was performed in this study. The dominant organic compound was bis(tert-butyldimethylsilyl) carbonate, which varied from 6.90% to 25.68% in peat extracts. The highest mass fraction of malonic acid amide was in the sapropel extract; it varied from 12.44% to 26.84%. Significant amounts of acetohydroxamic, lactic, and glycolic acid derivatives were identified in peat and sapropel extracts. Comparing the two extraction methods, it was concluded that active maceration was more efficient than ultrasound extraction in yielding higher amounts of organic compounds. The highest amounts of fulvic acid (1%) and humic acid and humin (15.3%) were determined in pure brown peat samples. This research on humic substances is useful to characterize the peat of different origins, to develop possible aspects of standardization, and to describe potential of the chemical constituents.

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