Measurement of Humic and Fulvic Acid Concentrations and Dissolution Properties by a Rapid Batch Procedure

Abstract

Although humic substances (HS) strongly facilitate the transport of metals and hydrophobic organic contaminants in environmental systems, their measurement is hampered by the time-consuming nature of currently available methods for their isolation and purification. We present and apply a new rapid batch method to measure humic (HA) and fulvic (FA) acid concentrations and dissolution properties in both solid and aqueous samples. The method is compared with the conventional procedures and is shown to substantially facilitate HS concentration measurements, particularly for applications such as geochemical modeling where HS purification is not required. The new method can be performed within 1.5-4 h per sample and multiple samples can be processed simultaneously, while the conventional procedures typically require approximately 40 h for a single sample. In addition, specific dissolution properties of HS are identified and are consistent with recent views on the molecular structure of HS that emphasize molecular interactions of smaller entities over distinct macromolecular components. Because the principles of the new method are essentially the same as those of generally accepted conventional procedures, the identified HA and FA properties are of general importance for the interpretation of the environmental occurrence and behavior of HS.

Nanoparticles in natural systems II: The natural oxide fraction at interaction with natural organic matter and phosphate

“…Hydrophilic acids (Hy), fulvic acids (FA), and humic acids (HA) have been separated using the method of Van Zomeren and Comans (2007). The concentration of dissolved C was measured with a TOC analyzer.…”

“…These numbers are substantially lower than the total carbon and NOM adsorption on natural oxide surfaces, which is $1.4 mg OC/m 2 or $2.5 mg NOM/m 2 as shown in part I (Hiemstra et al, 2010). The apparent amount of Table 1 The pH and phosphate concentration in 0.01 M CaCl 2 solution, and the corresponding speciation of DOC with hydrophilic acids (Hy), fulvic acids (FA), and humic acids (HA) using the method of Van Zomeren and Comans (2007). The data were collected 10 years after sampling of the Copernicus soil series.…”

“…Moreover, the DOC is represented by one type of molecule whereas it has been shown that natural DOC fraction is a mixture of different types of organic molecules such as fulvic (FA), humic (HA), and hydrophilic acids (Hy), which all have variable charge. For a limited set of eight samples, we have fractionated the DOC in the three above-mentioned fractions using the method of Van Zomeren and Comans (2007). As follows from Table 1, most carbon in the solution was present as hydrophilic acids, 76 ± 8%.…”

Unwanted metals and hydrophobic contaminants in bioreactor effluents are associated with the presence of humic substances

“…Like COD, TOC removal was not exceeded 50%. Generally, the carbon pollution could be divided into five major groups: (1) suspended solid, (2) hydrophobic organic carbon, such as fatty acids, grease and phenolic hydrocarbon (Aloui et al 2009), (3) humic acid, (4) fulvic acid, and (5) hydrophilic acid (van Zomeren & Comans 2007). The passage of the first group was blocked by the membrane, as no turbidity was detected in the outlet.…”

Closing the nutrient loops in (peri-)urban farming systems through composting

“…The batch fractionation procedure (Van Zomeren and Comans, 2007) fractions were estimated from the DOC that was not dissolved under alkaline conditions.…”