title: [Characterization of the different organic matter from soils and sediments].
abstract: The humic acid (HA) and nonhydrolyzable carbons (NHC) were isolated from three river sediment samples (1, 2, 3) from the rivers in the Tongzhou district of Beijing and four soil samples(4, 5, 6, and 7) from the surface soils in the vicinity area of Tianjin near Bohai Bay, respectively. The isolated HA and NHC fractions were also characterized using elementary analysis, X-ray photoelectron spectroscopy (XPS), solid state 13C cross-polarization and magic angle spinning nuclear magnetic resonance spectroscopy (13C NMR), and Fourier transformed infrared spectroscopy (FTIR). The results showed that NHC had lower H/ C and O/C atomic ratios than HA from the same source. The sum of surface O-containing groups accounted for 7.6%-10.7% and 40.9%-46.7% in NHC and HA samples, respectively. 13C NMR and FTIR spectra of the NHC samples revealed a large contribution of alkyl carbon and aryl carbon. In addition, the NHCs isolated from soils had higher content of aromatic carbon than the NHC form river sediments. Systematic characterization showed that the NHC samples were more condensed and hydrophobicity than the HA samples.
authors.affiliation: Department of Water Environment, China Institute of Water Resources and Hydropower Research, Beijing 100038, China. gaobo@iwhr.com
authors.forename: Bo
authors.initials: B
authors.lastname: Gao
authors.forename: Huai-Dong
authors.initials: HD
authors.lastname: Zhou
authors.forename: Jie
authors.initials: J
authors.lastname: Jin
authors.forename: Ke
authors.initials: K
authors.lastname: Sun