Fractions of organic matter and redox properties of humic substances in sediments from deep oceans

Quimica nova

Gobo, Arizoli Antonio Rosa¹  Salomão, Marcos Sarmet Moreira de Barros¹  Rezende, Carlos Eduardo¹  Baldotto, Marihus Altoé²  Camargo, Plínio Barbosa de³ 

[1] Universidade Estadual do Norte Fluminense Darcy Ribeiro, Campos dos Goytacazes, Brasil;Universidade Federal de Viçosa, Florestal, Brasil;Universidade de São Paulo, Piracicaba, Brasil

关键词: sediments;    organic carbon;    electrochemistry.;   

DOI  :  10.1590/S0100-40422013000900003

学科分类：化学（综合）

来源: Sociedade Brasileira de Quimica

【 摘 要 】

Previous studies have verified that free radicals such as quinone moieties in organic matter participate in the redox reactions in natural systems. These functional groups were positively correlated with the increase in aromaticity and hydrophobicity of the humic substances. As an alternative to relatively complex and expensive spectroscopic methods, the redox properties of the humic substances, determined by potentiometric titrations, have been used to evaluate organic carbon stability in soil and sediments. The present study aimed to perform organic matter fractionation and isolation of humic substances from deep oceans in different isobaths (750; 1,050; 1,350; 1,650; 1,950 m) to determine their redox properties by iodimetric titrations under an inert atmosphere and specified conditions of pH and ionic strength. Sediment samples were collected to the North and South of platforms of petroleum exploration located in the North of Rio de Janeiro State, Brazil. Fractions of organic carbon and redox properties of humic substances varied with origin and depth of the samples and with position North and South of the petroleum exploration area.

【 授权许可】

CC BY