title: Comprehensive comparison of the chemical and structural characterization of landfill leachate and leonardite humic fractions.
abstract: Humic substances (HS) are complex and heterogeneous mixtures of organic compounds that occur everywhere in the environment. They represent most of the dissolved organic matter in soils, sediments (fossil), water, and landfills. The exact structure of HS macromolecules has not yet been determined because of their complexity and heterogeneity. Various descriptions of HS are used depending on specific environments of origin and research interests. In order to improve the understanding of the structure of HS extracted from landfill leachate (LHS) and commercial HS from leonardite (HHS), this study sought to compare the composition and characterization of the structure of LHS and HHS using elemental composition, chromatographic (high-performance liquid chromatography (HPLC)), and spectroscopic techniques (UV-vis, FTIR, NMR, and MALDI-TOF). The results showed that LHS molecules have a lower molecular weight and less aromatic structure than HHS molecules. The characteristics of functional groups of both LHS and HHS, however, were basically similar, but there was some differences in absorbance intensity. There were also less aliphatic and acidic functional groups and more aromatic and polyphenolic compounds in the humic acid (HA) fraction than in the fulvic acid (FA) and other molecules (OM) fractions of both origins. The differences between LHS and HHS might be due to the time course of humification. Combining the results obtained from these analytical techniques cold improve our understanding of the structure of HS of different origins and thus enhance their potential use.
authors.affiliation: University of Liège, Gembloux Agro-Bio Tech, Walloon Center for Industrial Biology (CWBI), Passage des Déportés, 2, 5030, Gembloux, Belgium. atahiri@doct.ulg.ac.be.|Walloon Agricultural Research Centre (CRA-W), Department Life Sciences, Chaussée de Charleroi, 234, 5030, Gembloux, Belgium. atahiri@doct.ulg.ac.be.
authors.forename: Abdelghani
authors.initials: A
authors.lastname: Tahiri
authors.affiliation: University of Liège, Gembloux Agro-Bio Tech, Biological and Industrial Chemistry Unit, Passage des Déportés, 2, 5030, Gembloux, Belgium.
authors.forename: Aurore
authors.initials: A
authors.lastname: Richel
authors.affiliation: University of Liège, Gembloux Agro-Bio Tech, Walloon Center for Industrial Biology (CWBI), Passage des Déportés, 2, 5030, Gembloux, Belgium.
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Destain
authors.affiliation: Walloon Agricultural Research Centre (CRA-W), Department Life Sciences, Chaussée de Charleroi, 234, 5030, Gembloux, Belgium.
authors.forename: Philippe
authors.initials: P
authors.lastname: Druart
authors.affiliation: University of Liège, Gembloux Agro-Bio Tech, Walloon Center for Industrial Biology (CWBI), Passage des Déportés, 2, 5030, Gembloux, Belgium.
authors.forename: Philippe
authors.initials: P
authors.lastname: Thonart
authors.affiliation: University of Liège, Gembloux Agro-Bio Tech, Walloon Center for Industrial Biology (CWBI), Passage des Déportés, 2, 5030, Gembloux, Belgium.
authors.forename: Marc
authors.initials: M
authors.lastname: Ongena
keywords: FTIR; HPLC; Humic substances; Landfill leachates; Leonardite; MALDI-TOF; NMR; UV–vis