Study On Extraction And Characterization Of HA And FA

Humic substances, which are widely distributed in nature, mainly include humicacids and fulic acid, account for about50-80percent of the total organic compounds in thesoil, hydrosphere and ecosphere. Previous studies indicated that humic substances not onlyplay important roles in the environmental behaviour of organic contaminants and metalions.， but also form DBPs and THMs in the disinfection process of watertreatment.Obviously, the environmental behaviour of humic substances is interrelatedclosely with their structures. As organic polymer, humic substances from different sources,extraction methods and extraction times are different. So it is necessary to frantionate thehumic substances to relatively uniform fractions, which can help us understand this kindof substances and their behaviour more clearly.In this study, HA and FA extracted from East Lake and Liangzi Lake in differentseasons using standard method proposed by IHSS were characterized by elementalanalysis, ultraviolet-visible spectroscopy (UV-Vis), Fourier transform infraredspectroscopy (FT-IR), three-dimensional excitation emissionmatrix fluorescencespectroscopy(3DEEM). In the data analysis and characterization, parallel factor analysismethod (PARAFAC) is used, which is advanced in nearly years.The results indicated that：(1) Compared with HA, FA contained more oxygen-containing groups and aromatic structure, and had a deeper budding corruption.Compared with East Lake, Liangzi Lake’s HA and FA contained more oxygen-containinggroups, and fat structure, and had a deeper budding corruption.Element analysis showedthat the carboxylic acid content of HA and FA from the two lakes increased with thechange of the seasons.The ratios of (O+N)/C and O/C from East Lake and Liangzi Lake indifferent seasons were similiar, speculate that the polarity of HS is closely related withtheir Aromatic degrees and Oxygen functional groups.(2)UV-Vis analysis showed thatHA extracted from East Lake in autumn and LiangZi Lake in winter, FA extracted fromEast Lake in spring had a high degree of aromatic acid; E2/E3and E2/E4was irrelevantwith aromatic degree.(3)FT-IR spectra showed that the autumn HA contained more fat structure and-OH key, the C-O-C keys of the FA and HA in different seasons weresmaller.(4)3DEEM spectrum of the traditional analysis showed that, the HA samplesmainly contained three similar fluorescence peaks, humic-like peak, fulic-like peak andprotein-like peak; FA samples mainly contained similar one fulic-like peak, but the FAsamples from East Lake in summer HA a special humic-like peak.(5)Combined withparallel factor analysis with3DEEM spectrum analysis, HA and FA could be analysisedmore clearly. In this study the extracted HA samples contained four components，whichrepresented three kinds of materials: humic acid-like material, fulic-like material andprotein-like material, and the extracted FA samples contained four components, whichrepresented two kinds of materials:: humic acid-like material and fulic-like material. HAwas sensitive to explore the water pollution, but FA was not sensitive. This study showedthe water of East Lake had been polluted seriously, but the water LiangZi Lake wasquality good.