Study Of Organic Matter Structural Characters And HOCs Sorption Model In Surface Sediments From Pearl River

The organic matter (SOM) such as humic substance, kerogen, andblack carbon (BC) in the soils and sediments is highly heterogeneous andcomprise various complex organic macromolecules which exist mostly ascomplexes in soils and sediments. The relative abundance, characteristicsand structure of these SOM play an important role on the global carboncycles, the global climate changes, the transformation and fate of theorganic and inorganic pollutants, and the soil fertility. Therefore, it isimportant issue to quantified and characterized various SOM in soils andsediments. In this paper work the mineral - humus complex and itsstructure was studied, and the extraction and characterization of the SOMin the section of Pearl River in Guangzhou was carried out.The adsorption behavior of HOCs in soil and sediment affects thetransport, transformation, cycle and fate, as well as the bioavailability andbiological effects. So it is important to Study HOCs adsorption behavior insoils and sediments and/or the water body. Adsorption behavior wasinfluenced by many factors, such as Physico-chemical properties,composition and structure of the absorbent, environmental condition andcoexisting organic pollutants. Naphthalene sorption experiment was carriedout under condition of the room temperature.The paper was supported by National Nature Science Foundation(40373042)and Guangdong Nature Science Foundation(031504).The research results as follows:(1) The structure characters of organic matter in sediment weredetermined by using FI-IR, UV-Vis, FS, and XRD. The result showed thatthe organic matter has more aromatic rings and more unsaturated chemicalbonds.(2) The humic substance was extracted from original sediments withNaOH, the kerogen and black carbon were the residue that the mineral was dissolved. The result showed that the content of C , H, N, O is verydifferent in the separate product. The structure characters of kerogen andblack carbon were analyzed by using ¹³C-NMR.(3) We separated four different density mineral-organic complex bythe method of heavy liquid. The structure of complex was tested by IR,TEM, and ¹³C-NMR. They have similar structure which presents irregulargroup granular and different mineral-organic complex with differentorganic content.(4) The primary factor in controlling organic pollutant adsorptionbehaviors is the content and species of organic matter in sediments.Through the adsorption experiment study, the naphthalene assumes linearadsorption behaviors in original sediment, it can be can well simulatedwith the Freundlich model; The naphthalene adsorption behaviors in theresidue displayed obvious non-linearity, it can be can well fitted byLangmuir model with R² value be 0.9976.