Products Cited in Publications Worldwide Comparison of Techniques Used to Characterize Humic Substances and Evaluation of Their Applicability to Assess the Suitability of Such Substances Sourced from Wastewater Treatment Plants

Comparison of Techniques Used to Characterize Humic Substances and Evaluation of Their Applicability to Assess the Suitability of Such Substances Sourced from Wastewater Treatment Plants

Justyna Michalska; Jolanta Turek-Szytow; Agnieszka Dudło; Katarzyna Kowalska; Joanna Surmacz-Górska

DOI:

Abstract

Humic substances (HSs) are among the most widespread organic compounds existing in the natural environment. Due to their reactivity, HSs often constitute nuisance factors for the operation of wastewater treatment plants (WWTPs). However, the recovery of HSs from liquid by-products (LBPs) of the wastewater treatment process opens up opportunities for their utilization. Consequently, the chemical and structural characterization of HSs is the prerequisite for assessing their application feasibility. Therefore, this study aimed to compare conventional techniques intended for the characterization of HSs including ultraviolet-visible (UV-Vis), fluorescence (FL), and Fourier-transform infrared (FTIR) spectroscopy as well as scanning electron microscopy coupled with energy dispersive spectroscopy (SEM/X-EDS). The aforementioned methods were assessed regarding their suitability for determining the structure, properties, and possible utilization of HSs originating from LBPs of the wastewater treatment process based on model humic compounds (MHCs). Herein, the results obtained using UV-Vis spectroscopy were found to correspond with the outcomes of FL, SEM/X-EDX, and FTIR analyses of MHCs. The research demonstrates that UV-Vis spectroscopy may be efficiently applied as a simple tool to distinguish particular fractions of HSs and predict their properties. Moreover, this technique enables the evaluation of changes in the behavior of HSs in the presence of Ca2+. Accordingly, UV-Vis spectroscopy was found to provide preliminary information about the application potential of HSs. It was additionally revealed that the optical properties and fluorescence capacities of HSs are strongly dependent on their concentration. Therefore, focusing on the obtained results and literature data, this study recommends that the quantitative comparison of properties of HSs should be proceeded by the standardization of their concentration.

Keywords

fluorescence ; FTIR ; fulvic acids ; humic substances ; SEM/X-EDX ; UV-Vis

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Fulvic Acid

A425634479-66-390% (T)

Fulvic Acid

56.0/100g

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