An acidic-groups detection method and its application to analysis of Chinese humic acid samples

Autor: Xue Li, Wang Yuhao, Xiaoling Zhu, Jie Zhang, Baolei Jia, Xu Pengfei, Chen Qingshuang, Lujiang Hao
Jazyk: angličtina
Rok vydání: 2020
Předmět:
Fossil Fuels
010501 environmental sciences
Conductivity
01 natural sciences
Geographical Locations
Soil
chemistry.chemical_compound
Hydroxybenzoates
Hydroxides
Humic acid
Materials
Flow Rate
chemistry.chemical_classification
0303 health sciences
Multidisciplinary
Physics
Chemical Reactions
Classical Mechanics
Soil chemistry
Hydrogen-Ion Concentration
Chemistry
Separation Processes
Coal
Sodium hydroxide
Physical Sciences
Engineering and Technology
Medicine
Titration
Organic Materials
Research Article
China
Asia
Science
Materials Science
Hydrochloric acid
Fluid Mechanics
Fuels
Research and Analysis Methods
Continuum Mechanics
03 medical and health sciences
Phenols
Oxidation
Sodium Hydroxide
Electrodes
Humic Substances
Distillation
030304 developmental biology
0105 earth and related environmental sciences
Chromatography
Electric Conductivity
Chemical Compounds
Fluid Dynamics
Electrochemical Techniques
Energy and Power
chemistry
People and Places
Hydrochloric Acid
Acids
Zdroj: PLoS ONE, Vol 15, Iss 8, p e0238061 (2020)
PLoS ONE
ISSN: 1932-6203
Popis: The method of non-aqueous conductivity titration (NACT) of organic weak acids was applied to quickly and accurately determine the phenolic-hydroxyl and carboxyl-groups contents in humic acid. By varying the pH of the humic-acid sample, the concentration of the titrant, and the nitrogen-gas flow rate, the optimal titration conditions were determined to be a sample pH of 4, titrant concentration of 0.05 mol/L, and nitrogen-gas flow rate of 80 mL/min. Applying the detection method to p-hydroxybenzoic acid showed that its phenolic-hydroxyl content was 758.82±111.76 cmol/kg and carboxyl content was 744.44±51.11 cmol/kg. The theoretical phenolic-hydroxyl and carboxyl-groups contents of the p-hydroxybenzoic acid were 723.96 cmol/kg respectively, indicating that the method can accurately quantify the carboxyl and phenolic-hydroxyl groups in the sample. The NACT was used to measure the phenolic-hydroxyl and carboxyl-groups contents in humic acid quickly and accurately. In addition, 29 humic acid samples from 8 provinces of China covering the main humic-acid producing areas were collected and analyzed for acidic-groups content using the reported method.
Databáze: OpenAIRE
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