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•Waste cassava harvest biomass as a source of renewable chemicals.•Effect of pyrolysis temperature over raw bio-oil constituents.•Comprehensive characterization of bio-oils from ...cassava shoot system.•Nitrogen-containing compounds indicate secondary deoxygenation mechanism.
This work proposes the pyrolysis of the cassava plant shoot system biomass and a comprehensive chemical characterization of the resulting bio-oil. The highest yields of liquid products were obtained at 600 °C, with 12.6 % bio-oil (organic fraction), which presented the lowest total acid number of 65.7 mg KOH g−1. The bio-oil produced at 500 °C exhibited the highest total phenolic content of approximately 41 % GAE, confirmed by GC/MS analysis (33.8 % of the total area). FT-Orbitrap MS analysis found hundreds of oxygenated constituents in the bio-oils, belonging to the O2-7 classes, as well as nitrogen compounds from the Ny and OxNy classes. Higher pyrolysis temperatures resulted in more oxygenated phenolics (O4–7) undergoing secondary degradation and deoxygenation reactions, generating O2–3 compounds. Additional classes affected were O3–5N2–3, while O1–2N1 presented more stable compounds. These findings show that cassava bio-oils are promising sources of renewable chemicals.
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•Precise biomass characterization requires analytical techniques combination.•Analytical tools concomitantly explore molecular-microstructural biomass level.•Instruments progress ...allows analytical complex samples advances.•Biomass composition affects the bioconversion yield and production economy.•PAT, real-time monitoring, ensures economical and mass-energy balance process.
The trend in the modern world is to replace fossil fuels with green energy sources in order to reduce their environmental impact. The biorefinery industry, within this premise, needs to establish quantitative and qualitative analytical methods to better understand lignocellulosic biomass composition and structure. This paper presents chemical techniques (chromatography, thermal analysis, HRMS, FTIR, NIR, and NMR) and physicochemical techniques (XRD, optical and electron microscopy techniques – Confocal fluorescence, Raman, SPM, AFM, SEM, and TEM) for the microstructural characterization of lignocellulosic biomass and its derivatives. Each of these tools provides different and complementary information regarding molecular and microstructural composition of lignocellulosic biomass. Understanding these properties is essential for the design and operation of associated biomass conversion processing facilities. PAT, monitored in real-time, ensures an economical and balanced mass-energy process. This review aimed to help researchers select the most suitable analytical technique with which to investigate biomass feedstocks with recalcitrant natures.
•A HNO3 activated biochar was obtained from biochar of Eichhornia crassipes (400 °C).•A rGO/activated biochar nanocomposite was used as carbon paste electrodes modifier.•The developed sensor was ...successfully applied for the paraquat (PQ) determination.•PQ was determined in coconut water, honey, lettuce, lemon and wastewater samples.
A novel electrochemical sensor based on activated biochar (AB4) and reduced graphene oxide (rGO) was developed and tested for detection of paraquat (PQ) in food samples. Precursor biochar was obtained by the pyrolysis of water hyacinth biomass at 400, 500, and 600 °C, followed by a chemical activation step using HNO3 to increase the amount of oxygenated and nitrogenated groups. The modified electrodes (rGO–AB4) were tested in different experimental conditions, and exhibited good response under the optimized conditions, showing linearity from 0.74 to 9.82 μmol L−1 and a limit of detection and limit of quantification of 0.02 μmolL−1 and 0.07 μmol L−1, respectively. Interfering species such as glyphosate caused insignificant changes in the peak current of paraquat, and the selectivity of the method was tested using blank and spiked samples of coconut water, wastewater, honey, lettuce and lemon. Recovery ranged from 87.70±2.07% to 103.80±3.94%.
Organosolv pretreatment reactions with glycerol, applied to water hyacinth, were performed with evaluation of the effects of the following variables: time (10–120 min), temperature (100–220 °C), ...solid/liquid ratio (1–6%), water percentage (0–40%), and cobalt ferrite (CoFe2O4) catalyst percentage (0–10%). The objective was to optimize the process in order to maximize the yield of sugars in subsequent enzymatic hydrolysis. The optimized condition obtained using a 25−1 experimental design was as follows: time of 10 min, temperature of 220 °C, solid/liquid ratio of 6%, 0% water, and 0% catalyst, which resulted in 37% release of sugars. Other sources of iron were also tested (FeCl3 and FeSO4). Unlike CoFe2O4, these added iron salts presented activity, under the optimal condition. The use of FeSO4 and FeCl3 at 0.1 mol.L−1 increased the release of sugars to 41 and 51%, respectively. It was evident that the activity of the iron was determined by the form in which it was present. The findings contribute to understanding the action of iron and other metal salts in pretreatment reactions.
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•Optimization of the most important variables by experimental design 25−1.•First work on the pre-treatment of water hyacinth with iron-based catalysts.•First study that evaluated organosolv pretreatment with glycerol + CoFe2O4, FeCl3 and FeSO4.•The organosolv pretreatment with glycerol + FeCl3 showed promise.•Better understanding of the action of metallic salts in pretreatment reactions.
Multiple studies have focused on the effect of long-term weathering processes on oils after spill events, without considering the chemical compositional changes occurring shortly after the release of ...oil into the environment. Therefore, the present study provides a broad chemical characterization for understanding of the changes occurring in the chemical compositions of intermediate (°API = 27.0) and heavy (°API = 20.9) oils from the Sergipe-Alagoas basin submitted to two simulated situations, one under marine conditions and the other in a riverine environment. Samples of the oils were collected during the first 72 h of contact with the simulated environments, followed by evaluation of their chemical compositions. SARA fractionation was used to isolate the resins, which were characterized at the molecular level by UHRMS. The evaporation process was highlighted, with the GC-FID chromatographic profiles showing the disappearance of compounds from
n
-C
10
until
n
-C
16
, as well as changes in the weathering indexes and pristane +
n-
C
17
/phytane +
n-
C
18
ratios for the crude oils submitted to the riverine conditions. Analysis of the resins fraction showed that basic polar compounds underwent little or no alterations during the early stages of weathering. The marine environment was shown to be much less oxidative than the riverine environment. For both environments, a feature highlighted was an increase of acidic oxygenated compounds with the increase of weathering, especially for the crude oil with °API = 27.0.
•Production of bio-oils from domestic and industrial effluent stations sludges.•Majority of nitrogenous and ester compounds for bio-oils.•Bio-oils rich in polar nitrogenous compounds (Nx, and NxOx ...classes).•Presence of functionalized alkyl chains in both bio-oils.•Bio-oils may be sources of high added-value compounds.
The use of renewable sources for energy has increased due to the high demand of modern society and the environmental impacts caused by the use of fossil fuels. Environmentally friendly renewable energy production may involve thermal processes, including the application of biomass. We provide a comprehensive chemical characterization of sludges from domestic and industrial effluent treatment stations, as well as the bio-oils produced by fast pyrolysis. A comparative study of the sludges and the corresponding pyrolysis oils was performed, with characterization of the raw materials using thermogravimetric analysis, energy-dispersive X-ray spectroscopy, Fourier-transform infrared spectroscopy, elemental analysis, and inductively coupled plasma optical emission spectrometry. The bio-oils were characterized using comprehensive two-dimensional gas chromatography/mass spectrometry that identified compounds classified according to their chemical class, mainly related to nitrogenous (62.2%) and ester (18.9%) for domestic sludge bio-oil, and nitrogenous (61.0%) and ester (27.6%) for industrial sludge bio-oil. The Fourier transform ion cyclotron resonance mass spectrometry revealed a broad distribution of classes with oxygen and/or sulfur (N2O2S, O2, and S2 classes). Nitrogenous compounds (N, N2, N3, and NxOxclasses) were also found to be abundant in both bio-oils, due to the origins of the sludges (with the presence of proteins), making these bio-oils unsuitable for use as renewable fuels, since NOxgases could be released during combustion processes. The presence of functionalized alkyl chains indicated the potential of the bio-oils as sources of high added-value compounds that could be obtained by recovery processes and used for the manufacture of fertilizers, surfactants, and nitrogen solvents.
The contamination of terrestrial environments by oil spills creates biological risks to humans and affects the ecosystem’s health. The studies that aim to evaluate the toxicity and changes in the ...environments are a field of potential interest to the scientific community. The objective of this study was to evaluate the changes in the chemical composition of crude oil fractions after the simulation of a spill in soil and sand, with emphasis on an immediate temporal investigation. Samples of intermediate (°API = 27.0) and heavy (°API = 20.9) oils from Sergipe-Alagoas basin were used. The evaporation process in the soil was highlighted; while the GC-FID chromatographic profiles demonstrated (1) the disappearance from
n-
C
12
until
n-
C
14
compounds, besides a decrease of more than 50% in
n-
C
15
and
n-
C
16
n-
alkanes and (2) no changes in
n-
C
17
/Pr and
n-
C
18
/Ph ratios for both oils. Analysis of resins fraction performed by Orbitrap-MS has shown changes in the mass spectra profile and compound distribution during the soil and sand exposure process, with N
1
, O
1
, and O
2
species showing changes in the relative abundance in ESI(+) mode, and O
2
, N
1
, and O
1
for ESI(−). Changes in polar compounds of oil will depend on the extent of the time of interaction with soil and sand, taking into account intrinsic aspects, such as the nature of the soil and components in it as the organic matter.
Different ionization techniques based on different principles have been applied for the direct mass spectrometric (MS) analysis of crude oils providing composition profiles. Such profiles have been ...used to infer a number of crude oil properties. We have tested the ability of two major atmospheric pressure ionization techniques, electrospray ionization (ESI(±)) and atmospheric pressure photoionization (APPI(+)), in conjunction with Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). The ultrahigh resolution and accuracy measurements of FT-ICR MS allow for the correlation of mass spectrometric (MS) data with crude oil American Petroleum Institute (API) gravities, which is a major quality parameter used to guide crude oil refining, and represents a value of the density of a crude oil. The double bond equivalent (DBE) distribution as a function of the classes of constituents, as well as the carbon numbers as measured by the carbon number distributions, were examined to correlate the API gravities of heavy, medium, and light crude oils with molecular FT-ICR MS data. An aromaticity tendency was found to directly correlate the FT-ICR MS data with API gravities, regardless of the ionization technique used. This means that an analysis on the molecular level can explain the differences between a heavy and a light crude oil on the basis of the aromaticity of the compounds in different classes. This tendency of FT-ICR MS with all three techniques, namely, ESI(+), ESI(−), and APPI(+), indicates that the molecular composition of the constituents of crude oils is directly associated with API gravity.
In this study, ozonation of raw textile wastewater was conducted in a pilot-scale plant and the efficiency of this treatment was evaluated based on the parameters color removal and soluble organic ...matter measured as chemical oxygen demand (COD), at two pH values (9.1 and 3.0). Identification of intermediate and final degradation products of ozone pre-treatment, as well as the evaluation of the final ecotoxicity (Lumistox test) of pre-treated wastewater, was also carried out. After 4
h of ozone treatment with wastewater recirculation (flow rate of 0.45
m
3
h
−1) the average efficiencies for color removal were 67.5% (pH 9.1) and 40.6% (pH 3.0), while COD reduction was 25.5% (pH 9.1) and 18.7% (pH 3.0) for an ozone production capacity of 20
g
h
−1. Furthermore, ozonation enhances the biodegradability of textile wastewater (BOD
5/COD ratios) by a factor of up to 6.8-fold. A GC-MS analysis of pre-treated textile wastewater showed that some products were present at the end of the pre-treatment time. In spite of this fact, the bacterial luminescence inhibition test (Lumistox test) showed a significant toxicity reduction on comparing the raw and treated textile wastewater. In conclusion, pre-ozonation of textile wastewater is an important step in terms of improving wastewater biodegradability, as well as reducing acute ecotoxicity, which should be removed completely through sequential biological treatment.
A simple, efficient, environmentally friendly, and inexpensive synthesis route was developed to obtain a magnetic nano-hybrid (GH) based on graphene and cobalt ferrite. Water with a high content of ...natural organic matter (NOM) was used as solvent and a source of carbon. The presence of NOM in the composition of GH was confirmed by FTIR and Raman spectroscopy, which evidenced the formation of graphene, as also corroborated by XRD analyses. The diffractograms and TEM images showed the formation of a hybrid nanomaterial composed of graphene and cobalt ferrite, with crystallite and particle sizes of 0.83 and 4.0 nm, respectively. The heterogeneous electro-Fenton process (EF-GH) achieved 100% degradation of bisphenol A (BPA) in 50 min, with 80% mineralization in 7 h, at pH 7, using a current density of 33.3 mA cm
−2
. The high catalytic performance was achieved at neutral pH, enabling substantial reduction of the costs of treatment processes. This work contributes to understanding the role of NOM in the synthesis of a magnetic nano-hybrid based on graphene and cobalt ferrite, for use in heterogeneous catalysis. This nano-hybrid has excellent potential for application in the degradation of persistent organic pollutants found in aquatic environments.
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