三峡库区消落带腐殖酸的表面增强拉曼光谱

SURFACE ENHANCED RAMAN SPECTROSCOPIC CHARACTERIZATION OF HUMIC ACID FROM THE WATER LEVEL FLUCTUATION ZONE OF THE THREE GORGES RESERVOIR AREA

选择三峡库区(TGRA)沿岸6个典型段面,分别在145 m和175 m水位,采集土壤和沉积物样品,提取并纯化了腐殖酸(HA),获得各段面HA的红外、拉曼及其在金/银核-壳复合粒子上的表面增强拉曼散射(SERS)光谱,着重探讨了TGRA中HA的SERS与土壤类别、利用方式、水位消落引起的土壤特性变化(pH,ORP,腐殖化程度)等因素的关系.研究显示,1789—1732 cm-1的ν(—C O),δ(CH),H键缔合ν(—C O)及低波数τ(NH),δ(COO—),γ(C—O)等为库区HA的特征振动,4类土壤HA的红外主要在1454—1435 cm-1有无δ(CH2),1300—900 cm-1和800 cm-1下有无基团或骨架振动等表现出差异,以黄壤与棕壤HA结构差异最显著,红壤HA的SERS中,ν(C—C),τ(CH),δ(CH2)的增强峰有明显区别.各沉积物的腐殖化程度均有提高,下游段面沉积物HA的SERS较强.

oil and sediments were collected at water level of 145 m and 175 m in six representative areas of the water fluctuation zone of the Three Gorges Reservoir Area（TGRA）.Humic acids were isolated from those samples,purified and characterized by IR,Raman and surface enhanced Raman scattering spectra adsorbed on the core-shell Au/Ag nanoparticles.The relationship of HA′ SERS with the types of soil,soil usage and soil properties（pH,ORP,humification degree et al.）caused by the water level fluctuation,was evaluated.According to the results,in 1789—1732 cm-1 ν（—CO）,δ（CH）,associated H bond ν（—CO） and in low wave numbers′ τ（NH）,δ（COO—）,γ（C—O） are the characteristic vibrations of the HAs in the TGRA;HA′s structure of yellow soil is notable different from brown soil′s based on the IR spectra of the HAs from 4 sorts of soils,as compared by 1454—1435 cm-1′s δ（CH2）,1300—900 cm-1 and 800 cm-1′s vibration of groups,skeleton et al.The difference of HA vibrational structures between yellow soil and brown soil are most.SERS of the red soil′s HA have distinctly enhanced peaks showed ν（C—C）,τ（CH）,δ（CH2） from other three types of soils.The humification degrees in the sediments are increased comparing with the corresponding soils,and the SERS of HA from the downstream sites′ sediments are enhanced more.