Solubility of Benzo[a]pyrene and Organic Matter of Soil in Subcritical Water

Abstract

A dynamic subcritical water extraction method of benzo [a]pyrene from soils is under consideration. The optimum conditions for benzo [a]pyrene extraction from soil are described including the soil treatment by subcritical water at 250 °C and 100 atm for 30 min. The effectiveness of developed method was determined using the matrix spiking recovery technique. A comparative analysis was made to evaluate the results of benzo[a]pyrene extraction from soils using the subcritical water and organic solvents. The advantages of the subcritical water extraction involve the use of ecologically friendly solvent, a shorter time for the analysis and a higher amount of benzo[a]pyrene extracted from soil (96 %). The influence of subcritical water extraction on soil properties was measured the investigation of the processes occurring within soil under the influence the high temperature and pressure. Under appropriate conditions of the experiment there is the destruction of the soil organic matter while the composition of the soil mineral fraction remains practically unchanged.

Subcritical water extraction of organic acids from chicken manure

“…It was found a decreasing of the inorganic carbon content under the subcritical water heating at 250 °C up to 3.2 × 10 −6 g kg −1 . The results found corresponded to previous research showing a slight decrease in the inorganic carbon content with increasing subcritical water temperature 30 …”

“…The С org and N total maximum amounts were extracted by subcritical water from the chicken manure at a temperature of 250 °C and amounted 3650.5 × 10 −6 g kg −1 and 324.0 × 10 −6 g kg −1 respectively, and they decreased with decreasing extraction temperature. The data obtained corresponds to those of a previous investigation showing a high increase in the organic carbon content under a subcritical water temperature increase up to 250 °C 30 . The main contribution has a carbon of organic origin – more than 90% from C total .…”

“…The data obtained corresponds to those of a previous investigation showing a high increase in the organic carbon content under a subcritical water temperature increase up to 250°C. 30 The main contribution has a carbon of organic originmore than 90% from C total . The ratio of the relative carbon and nitrogen content (С total :N total ) is 12:1 and, practically, does not change with increasing temperature.…”

“…The results found corresponded to previous research showing a slight decrease in the inorganic carbon content with increasing subcritical water temperature. 30 IR spectroscopy allows the study of the functional groups included in the structure of organic acids. The IR spectra obtained from the samples are shown in Fig.…”

Investigating the possibility of using subcritical water for extracting polycyclic aromatic hydrocarbons from soils of the dry-steppe zone

“…Subcritical aqueous method of processing chicken manure allowed to obtain a liquid extract containing organic acids, characterized by the presence of basic functional groups, high content of organic carbon and trace elements . Subcritical and supercritical states of water were used as extractants in the extraction of some individual PAH compounds (benz(a)pyrene, phenanthrene, fluoranthene, pyrene) from Calcic Chernozems, Andosols, sandy substrates and sewage sludge (Islam et al, 2013;Sushkova et al, 2013Sushkova et al, , 2014Sushkova et al, , 2015Yabalak et al, 2024). The development of pollutant extraction technology for qualitative assessment of ecosystem ecological state requires selecting conditions and testing the method of subcritical water extraction of the entire pool of priority PAHs for soils most vulnerable to pollution.…”