Chemical Properties And Fluorescence Characteristics Of National Colloidal Particles In Liaohe Basin

Natural water is a complex disperse system, in which the special functions of natural nanoparticles with particle diameter of lnm～1μm and colloidal components could influence the geochemical cycle of aquatic elements and the rule of transportation and transformation of the aquatic pollutants, thereby lead the production of aquatic pollutants and variations of their occurrence state and bio-availability. There are various dispersing colloidal particles, such as inorganic colloid like mineral particles, organic colloid and living matter colloid like algae and bacteria. The comparatively large surface area and intensive adsorptivity of colloidal particles make the particles incline to interface interact with trace organic and inorganic pollutants in natural water, and finally determine the transportation and environmental fate of the pollutants. Thus, it is important and necessary to focus on research of the chemical composition and fluorescence characteristic of aquatic colloidal particles. Using natural colloid from Liaohe river catchment as research subject, this study investigates the distribution characteristics of organic carbon, ions and heavy metal and the sizing characteristics of colloidal particles and the fluorescence characteristics of organic particles with different diameters. Meanwhile, this paper also researches aquatic environmental behaviors of natural colloidal particles in and rules of transportation and transformation of pollutants in by colloidal model simulation and fluorescence quenching analysis.The colloidal organic carbon in Liaohe Basin accounts for44.47%～85.04%of total dissolved organic carbon. The negative ions, such as, F-, Cl-, NO2-, Br-, SO42-and etc, were mainly in dissolved form with diameter<1kDa. And most metal elements in Puhe river and Haichenghe river exist in dissolved form, whereas metal elements in Xihe river exist in big colloidal form. Besides, there is no significant relationship among organic carbon, negative ions and metal ion in Liaohe river.The result of three dimensional fluorescence spectra show that the tryptophan-, tyrosine-, fuvic-and humic-like materials were present in the waters from Liaohe Basin, of which fuvic-and humic-like materials were mainly in colloidal form with small size (<100kDa) and truly dissolved phase (UOM,<1kDa). The adsorption of protein-like matters onto the colloid particles made the majority of these materials in colloidal phase though they were low molecular weight. Fluorescence index indicated that humic-like components in truly dissolved phase were mainly originated from autochthonous source and colloidal humic-like components were mainly derived from terrestrial organic matter. The humic-like matter was domain of dissolved organic carbon content, but the contribution of protein-like materials to the organic carbon was not negligible due to the waterbody polluted to the some extent by industrial wastewater discharge.The result of three dimensional fluorescence spectrum analysis of the DOM in Liaohe river by parallel factor analysis show that there are10fluorescence components, which involves humic-like type, SRFA-like type and protein-like type fluorescence components, in DOM. Humic-like and SRFA-like fluorescence components account a large proportion of UOM, while the proportion of protein-like fluorescence components is comparatively large in COM大, namely, humic-like and SRFA-like fluorescence components are primarily in dissolved form with diameter<1kDa and protein-like fluorescence component mainly exist in big colloidal form with diameter of100kDa～0.45μm, which is corresponding with the three dimensional fluorescence spectrum analysis.The effects of nano-meter ferric oxide content, pH and mixing time on fluorescence quenching of dissolved humic-like fluorescence component are investigated in this paper. The results indicate that the fluorescence peak position of non-standard humic acid is Ex/Em=240～270nm/400～480nm, and the fluorescence peak position and intensity of humic acid change little with the increase of mixing time. Furthermore, the fluorescence peak intensity decreases sharply with the increase of ferric oxide, meanwhile, the fluorescence quenching becomes obvious. The intensity of fluorescence quenching reaches the maximum of0.21with pH of4,humic acid concentration of10mg·L-1and ferric oxide content of50mg·L-1.