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1.
Environ Monit Assess ; 196(7): 595, 2024 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-38833198

RESUMO

Aquatic humic substances (AHS) are defined as an important components of organic matter, being composed as small molecules in a supramolecular structure and can interact with metallic ions, thereby altering the bioavailability of these species. To better understand this behavior, AHS were extracted and characterized from Negro River, located near Manaus city and Carú River, that is situated in Itacoatiara city, an area experiencing increasing anthropogenic actions; both were characterized as blackwater rivers. The AHS were characterized by 13C nuclear magnetic ressonance and thermochemolysis GC-MS to obtain structural characteristics. Interaction studies with Cu (II), Al (III), and Fe (III) were investigated using fluorescence spectroscopy applied to parallel factor analysis (PARAFAC) and two-dimensional correlation spectroscopy with Fourier transform infrared spectroscopy (2D-COS FTIR). The AHS from dry season had more aromatic fractions not derived from lignin and had higher content of alkyls moities from microbial sources and vegetal tissues of autochthonous origin, while AHS isolated in the rainy season showed more metals in its molecular architecture, lignin units, and polysacharide structures. The study showed that AHS composition from rainy season were able to interact with Al (III), Fe (III), and Cu (II). Two fluorescent components were identified as responsible for interaction: C1 (blue-shifted) and C2 (red-shifted). C1 showed higher complexation capacities but with lower complexation stability constants (KML ranged from 0.3 to 7.9 × 105) than C2 (KML ranged from 3.1 to 10.0 × 105). 2D-COS FTIR showed that the COO- and C-O in phenolic were the most important functional groups for interaction with studied metallic ions.


Assuntos
Alumínio , Cobre , Monitoramento Ambiental , Substâncias Húmicas , Rios , Estações do Ano , Poluentes Químicos da Água , Substâncias Húmicas/análise , Rios/química , Espectroscopia de Infravermelho com Transformada de Fourier , Monitoramento Ambiental/métodos , Poluentes Químicos da Água/análise , Cobre/análise , Alumínio/análise , Alumínio/química , Ferro/análise , Ferro/química , Brasil , Análise Fatorial
2.
Ecotoxicol Environ Saf ; 205: 111173, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32853866

RESUMO

Fulvic acids (FA) are one of the components of humic substances and play an important role in the interaction with metallic species and, consequently, the bioavailability, distribution and toxicity of metals. However, only a few studies have investigated these FA properties in specific environment, such as anthropogenic soils. Therefore, knowledge about FA molecular composition as well as the FA-metal interaction is essential to predict their behavior in the soil. For this reason, the aim of this study was to investigate the molecular composition of FA extracted from two sites in an anthropogenic soil (Terra Mulata), from the Amazon region, as well as their interactions with Cu(II) ions as a model. Results from 13C NMR, infrared and elemental analysis showed that these FA are composed mostly by alkyl structures and oxygen-functional groups, e.g., hydroxyl, carbonyl and carboxyl. The interaction with Cu(II) ions was evaluated by fluorescence quenching, in which the FA showed both high quantity of complexing sites per gram of carbon and good affinity to interact with the metal when compared with other soil FA. The results showed that the complexation capacity was highly correlated by the content of functional groups, while the binding affinity was largely influenced by structural factors. In addition, through the lifetime decay given by time-resolved fluorescence, it was concluded that static quenching took place in FA and Cu(II) interaction with the formation of a non-fluorescent ground-state complex. Therefore, this fraction of soil organic matter will fully participate in complexation reactions, thereby influencing the mobility and bioavailability of metal in soils. Hence, the importance of the study, and the role of FA in the environment, can be seen especially in the Amazon, which is one of the most important biomes in the world.


Assuntos
Benzopiranos/análise , Complexos de Coordenação/análise , Cobre/análise , Substâncias Húmicas/análise , Poluentes do Solo/análise , Solo/química , Benzopiranos/química , Disponibilidade Biológica , Brasil , Carbono/análise , Complexos de Coordenação/química , Cobre/química , Fluorescência , Íons , Modelos Teóricos , Poluentes do Solo/química
3.
Chemosphere ; 256: 127110, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32464361

RESUMO

Organic matter plays many roles in the soil ecosystem. One property of the substance concerns the metal complexation and interaction with organic contaminants. In this sense, the humic substances (HS), a heterogeneous mixture of compounds, naturally derived from degradation of biomass, have been widely studied in environmental sciences. Recent advances showed a new way to produce humic-like substances (HLS) through hydrothermal carbonization of biomass. Thus, this study aimed to evaluate the HLS of hydrochars, produced by using a mixture of sugarcane bagasse and vinasse with sulfuric acid added (1 and 4% v/v), and to assess their interactions with metal ions, (Fe(III), Al(III), Cu(II) and Co(II)) using EEM-PARAFAC and a two-dimensional FTIR correlation analysis. The results were compared to the humic substances extracted from the Amazonian Anthrosol, as a model of anthropogenic organic matter. NMR analysis showed that humic-like extracts from hydrochar are mainly hydrophobic, while the soil has a greater contribution of polar moieties. The HLS and HS showed similar complexation capacities for Fe(III), Al(III) and Cu(II) assays. For Co(II) HLS exhibited larger affinities than HS. Two-dimensional correlation analysis FTIR showed that chemical groups may undergo conformational alteration with metal additions to achieve more stable arrangements (higher stability constant). Therefore, these results contribute more knowledge about the mechanism of HS and metal ion interaction, as well as showing that HTC can be an interesting option for HLS production, to be used as humic based materials.


Assuntos
Carvão Vegetal/química , Substâncias Húmicas/análise , Metais Pesados/química , Solo/química , Sítios de Ligação , Brasil , Ecossistema , Interações Hidrofóbicas e Hidrofílicas , Íons , Espectroscopia de Infravermelho com Transformada de Fourier
4.
Environ Sci Pollut Res Int ; 26(9): 9137-9145, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30715701

RESUMO

Hydrothermal carbonization transforms biomass into value-added material called hydrochar. The release of nutrients (P, N, Ca, Mg, and K) and organic carbon (TOC) from hydrochar in different extractive solutions was investigated in this study. Two sets of hydrochar were produced: (i) hydrochar prepared from sugarcane bagasse and vinasse mixture (BV-HC) and (ii) hydrochar prepared by the addition of H3PO4 to this mixture (BVA-HC). Both hydrochar types released significative amounts of nutrient and organic carbon, mainly Ca (5.0 mg g-1) in the mixture (KCl, K2SO4, NaOH, 1:1:1) extractive solution and TOC (72.6 mg g-1) in the NaOH extractive solution, for BV-HC. Nutrient release was influenced by pH and ionic strength. The release of P, Ca, and Mg was affected by the presence of insoluble phosphate phases in BVA-HC. The release of nutrients P, N, Ca, Mg, and K and organic carbon demonstrated that hydrochar has potential for soil application purposes.


Assuntos
Carbono/análise , Resíduos Industriais/análise , Nutrientes/análise , Extratos Vegetais/análise , Saccharum/química , Resíduos/análise , Cálcio/análise , Cálcio/isolamento & purificação , Carbono/isolamento & purificação , Celulose/química , Nutrientes/isolamento & purificação , Extratos Vegetais/isolamento & purificação , Solo/química
5.
Environ Sci Pollut Res Int ; 26(27): 27579-27589, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29594880

RESUMO

Hydrothermal carbonization (HTC) is a thermochemical process carried out in an aqueous medium. It is capable of converting biomass into a solid, carbon-rich material (hydrochar), and producing a liquid phase (process water) which contains the unreactive feedstock and/or chemical intermediates from the carbonization reaction. The aim of this study was to evaluate the characteristics of process water generated by HTC from vinasse and sugarcane bagasse produced by sugarcane industry and to evaluate its toxicity to both marine (using Artemia salina as a model organism) and the terrestrial environment (through seed germination studies of maize, lettuce, and tomato). The experiments showed that concentrated process water completely inhibited germination of maize, lettuce, and tomato seeds. On the other hand, diluted process water was able to stimulate seedlings of maize and tomato and enhance root and shoot growth. For Artemia, the LC50 indicated that the process water is practically non-toxic; however, morphological changes, especially damages to the digestive tube and antennas of Artemia, were observed for the concentration of 1000 mg C L-1.


Assuntos
Carbono/química , Saccharum/química , Biomassa , Germinação , Indústrias , Lactuca/química , Solanum lycopersicum/química , Sementes/química , Água , Zea mays/química
6.
Bioresour Technol ; 237: 213-221, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28433583

RESUMO

In this study, nutrients were immobilized on the hydrochars obtained by hydrothermal carbonization (HTC) of a vinasse and sugarcane bagasse mixture, in the presence of acid, base and salt additives at temperatures of 150, 190 and 230°C. The increase in temperature caused higher immobilization of Ca, Mg, K, N, Cu, Mn, Zn, B, P and Fe in all hydrochars produced. H3PO4 and NaOH immobilized higher amounts of P, Mg and Mn, while Ca was immobilized in higher quantities in the presence of H3PO4 and (NH4)2SO4. The addition of H2SO4, H3PO4 and (NH4)2SO4 was responsible for an increased immobilization of P, N, Ca, Mg and K. The immobilization of B, not present in the starting raw material, was possible with the addition of H3BO3. The results showed that it is possible to alter the reaction medium to immobilize nutrients on hydrochars produced from vinasse and sugarcane bagasse, for agricultural applications.


Assuntos
Eliminação de Resíduos , Saccharum , Nitrogênio , Fósforo , Temperatura
7.
Sci Total Environ ; 506-507: 234-40, 2015 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-25460956

RESUMO

Humic substances (HS) vary according to the physical and chemical factors present in the environment. Thus, the characterization of HS is very important because it improves the understanding of the groups that comprise the chemical structure. Sediment HS were extracted from four locations representative of sugar cane cultivation, pasture, urban area and the impoundment of the Água Vermelha Hydroelectric Power Plant. Characterization using nuclear magnetic resonance (NMR) allowed us to infer that the HS from an area predominantly characterized by sugar cane cultivation (41.9%) and a typical rural area (35.0%) showed the highest aromaticity percentage. Using the off-line TMAH-thermochemolysis-GC-MS, we inferred that the HS of a typical rural area had a structure rich in plant waxes, plant biopolyester and a large amount of fatty acid methyl ester, which are related to the large amount of humic acid in the structure. The HS samples from the sugar cane cultivation area and the impoundment receiving all of the pollution load from the Turvo/Grande Hydrographic Basin (Bacia Hidrográfica do Turvo/Grande-BHTG) contained contributions from compounds rich in lipids and fatty acid methyl esters, highlighting the presence of the breakdown of petroleum-derived hydrocarbons in the area receiving the entire pollution load. We conclude that the HS extracted from the sediments of the Preto, Turvo and Grande rivers showed well-defined characteristics that varied depending on soil use and occupation, especially the HS extracted from sediments sampled in areas typically planted with sugar cane and rural areas, whose structures contained more aromatic groups.


Assuntos
Monitoramento Ambiental , Sedimentos Geológicos/química , Substâncias Húmicas/análise , Rios/química , Poluentes da Água/análise , Brasil , Cromatografia Gasosa-Espectrometria de Massas , Espectroscopia de Ressonância Magnética , Solo/química , Poluentes da Água/química
8.
Chemosphere ; 85(1): 97-105, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21683976

RESUMO

Fossil fuels such as diesel are being gradually replaced by biodiesel, a renewable energy source, cheaper and less polluting. However, little is known about the toxic effects of this new energy source on aquatic organisms. Thus, we evaluated biochemical biomarkers related to oxidative stress in Nile tilapia (Oreochromis niloticus) after two and seven exposure days to diesel and pure biodiesel (B100) and blends B5 and B20 at concentrations of 0.01 and 0.1 mL L(-1). The hepatic ethoxyresorufin-O-deethylase activity was highly induced in all groups, except for those animals exposed to B100. There was an increase in lipid peroxidation in liver and gills in the group exposed to the higher concentration of B5. All treatments caused a significant increase in the levels of 1-hydroxypyrene excreted in the bile after 2 and 7d, except for those fish exposed to B100. The hepatic glutathione-S-transferase increased after 7d in animals exposed to the higher concentration of diesel and in the gill of fish exposed to the higher concentration of pure diesel and B5, but decreased for the two tested concentrations of B100. Superoxide dismutase, catalase and glutathione peroxidase also presented significant changes according to the treatments for all groups, including B100. Biodiesel B20 in the conditions tested had fewer adverse effects than diesel and B5 for the Nile tilapia, and can be suggested as a less harmful fuel in substitution to diesel. However, even B100 could activate biochemical responses in fish, at the experimental conditions tested, indicating that this fuel can also represent a risk to the aquatic biota.


Assuntos
Biocombustíveis/toxicidade , Gasolina/toxicidade , Estresse Oxidativo , Tilápia/metabolismo , Animais , Catalase/metabolismo , Citocromo P-450 CYP1A1/metabolismo , Brânquias/metabolismo , Glutationa Transferase/metabolismo , Peroxidação de Lipídeos , Superóxido Dismutase/metabolismo , Poluentes Químicos da Água/toxicidade
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