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Results of efficiency of obtaining humic substances (HSs) from peat in traditional alkaline extraction (TAE) and ultrasound-assisted alkaline extraction (UAAE) are presented. The influence of the duration of the process and ultrasound intensity on the efficiency of extraction of humic acids (HAs) and fulvic acids (FAs) extraction was determined. The composition of the fulvic acid fraction was examined depending on the type of eluent used. Fulvic acids were divided into fractions using columns packed with DAX-8 resin. For this process, 0.1 M NaOH and 0.5 M NH3∙H2O were used as eluents. For the quality assessment of specific fulvic acids fractions, spectroscopic methods (UV-Vis and FTIR) were used. Ultrasound had a positive effect on HS extraction efficiency, especially in increasing the amount of a desired hydrophobic fraction of fulvic acids (HPO). However, a negative effect of the excessive prolongation and ultrasound intensity (approximately 400 mW∙cm−2) on the extraction efficiency of HPO eluted with 0.1 M NaOH solution was observed. Using peat as a raw carbon material for the HS extraction process can be used as an alternative industrial application of peat. UAAE may be considered as an alternative method to TAE, which provides a higher efficiency in HS isolation from peat. [ABSTRACT FROM AUTHOR]

Humic substances are widely applied in many branches of the industry. Their most well-known usage are agricultural and horticultural markets. A popular method of obtaining of mentioned compounds with satisfactory efficiency is an alkaline extraction of them from organic raw materials like peat, leonardite or lignite. The growing use of humic acids preparations is conditioned by improvement of physical, chemical and biological properties of soils. Despite that fact, the use of mineral fertilizers still dominates. Therefore, it seems interesting to produce agents containing both humic substances and traditional fertilizing elements. Such products could be applied as soil improvers. For that reason we have modified the International Humic Substances Society (IHSS) method of humic substances extraction by changing types of extractants and other solutions into solutions of main macroelements (NPK) for plants. The aim of this research was to determine the efficiency of humic acids extraction from polish peat depending on process temperature, its duration and concentration of extractant. [ABSTRACT FROM AUTHOR]