Characterization of humic substances extracted from hydrochar and terra mulata soil from Amazon Region

Abstract

In several regions of Amazon are found soils of pre-colombian origin and known as Terra Mulata, abundant in organic material as well as other macro and micronutrients, which guarantees high fertility taking humic substances as an important role. Many studies have sought to produce hydrochar, solid material abundant in carbon and nutrients from the hydrothermal carbonization of several humid biomasses. Considering the high availability of lignocellulosic biomass in Brazil, to highlight sugarcane bagasse and vinasse, this work has the main objective to produce hydrochar, followed by comparison of humic substances characteristics (humic acid - HA, fulvic acid - FA and Humin-H) present in this one with those found in Terra Mulata of the Amazon. For this to happen, the carbonization of vinasse and sugarcane bagasse as well as the re-carbonization of the "água mãe" in the presence of sulfuric and phosphoric acid will be done. HA, FA and H will be extracted from Terra Mulata and hydrochars produced following a methodology suggested by the International Humic Substances Society. In all samples will be made caracterization of humic and fulvic acids using UV-VIS Spectrophotometry, Molecular Fluorescence Spectroscopy, Infrared Spectroscopy, Elementary Analysis, and Cation Exchange Capacity. Then, it is expected that with the characterization of humic and fulvic acids it is possible to better understand the characteristics of the hydrochars allowing the understanding of the action in the soil, aiming its application as fertilizer. Once identified the characteristics of their humic substances, it will be possible to understand how the reaction conditions used in the production of the hydrochars modify the structures of the humic substances of them, making possible the determination of which reaction condition best meets the needs so that it acts as soil conditioning. (AU)