DQFA-Artículos
URI permanente para esta colecciónhttps://hdl.handle.net/10953/276
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Examinando DQFA-Artículos por Autor "Aranda-Sanjuán, Víctor"
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Ítem Analytical pyrolysis (Py-GC-MS) for the assessment of olive mill pomace composting efficiency and the effects of compost thermal treatment(Elsevier, 2022) Peña-Rueda, Marta; Comino-Romero, Francisco; Aranda-Sanjuán, Víctor; Domínguez-Vidal, Ana; Ayora-Cañada, María JoséComposting is an interesting solution for recycling the large amount of residues typically generated in olive oil production areas, particularly olive mill pomace. Bulking agents must be added to wet olive mill pomace for composting. The diversity of the materials used (such as olive tree-pruning residues, animal manure, or straw) and the variable proportion, in which they are mixed, are responsible for the heterogeneity and variability of the quality of the produced compost. For this reason, a comprehensive characterization of compost organic matter is necessary to gain information about its stability and maturity useful as well as to predict its behavior as a soil amendment. In this work, fresh olive mill pomace and four composted olive mill pomace samples were characterized using analytical pyrolysis coupled with gas chromatography and mass spectrometry (Py-GC-MS). Results showed a large variety of pyrolysis products, many of which had a specific biochemical origin. Pyrolysis-GC-MS revealed a decrease in fatty acids and aliphatic compounds content with composting, along with carbohydrates degradation and an increase in phenolic and N-compounds levels. Furthermore, the differences observed in organic matter characteristics had an impact on agronomic aspects (water repellency and phytotoxicity). Thus, the occurrence of fatty acids in incompletely composted materials (mainly palmitic and cis-vaccenic acids) was associated with increased phytotoxicity and higher water repellency. The presence of chicken manure in the mixtures was proved to favor the humification process and the production of stabilized compost (characterized by a lower Aliphatic-C/Aromatic-C ratio and higher N-heterocycles content). Furthermore, in this work, the effectiveness of applying thermal treatments to improve compost quality has been evaluated. Analysis of the Py-GC-MS results by means of principal component analysis (PCA) revealed thermal rearrangement, predominantly aromatization, and loss of functional groups of carbohydrates, lignin, and proteins, at temperatures above 225 ºC. Interestingly, the results suggest that materials with a non-effective or incomplete composting process can be transformed by thermal treatment into more stable products, exhibiting similar agronomic characteristics as those have that undergone a more efficient biotransformation.Ítem Monitoring organic matter transformation of olive oil production residues in a full-scale composting plant by fluorescence spectroscopy(Elsevier, 2024-08) Peña-Rueda, Marta; Domínguez-Vidal, Ana; Llorent-Martínez, Eulogio; Aranda-Sanjuán, Víctor; Ayora-Cañada, María JoséComposting wet olive mill pomace, the main by-product of two-phase centrifugation systems, is an attractive valorization strategy in the context of regenerative agriculture. A comprehensive study of the changes in fluorescence signatures during the co-composting of this residue with olive tree pruning wastes and animal manure in a full-scale composting plant was performed. This compost showed more complex features than others at the initial stages of the process, exhibiting a singular band in the synchronous spectrum (500 nm) here attributed to polyphenol-pectin interactions. PARAFAC-derived components from Excitation-Emission matrices (EEMs) of water extracts were compared with those of fractions isolated following alkaline extraction at different maturity stages. The increase with composting of the component associated with humic-like substances (Ex 225, 365 nm/Em 476 nm) was more marked in the isolated humic acid fraction than in water extracts. Thus, the predominance of fulvic-like substances in water extracts explains inconsistencies previously reported about the relevance of the humic-like component during the composting process and the extent of humification. Finally, the correlation between PARAFAC components and several compost maturity parameters was studied. The negative correlation between the protein-like component and the germination index was explained by the protein-polyphenol interactions reflected in the emission spectra of this component. A strong positive correlation between both fulvic and humic fluorescent components and cation exchange capacity was found. In general, mature compost showed C/N ≤ 20 and no phytotoxicity (GI around 60%) although differences related to the heterogeneity of the large composting pile were important.Ítem Understanding the compositional changes of organic matter in torrefied olive mill pomace compost using infrared spectroscopy and chemometrics(Elsevier, 2023) Peña-Rueda, Marta; Comino-Romero, Francisco; Aranda-Sanjuán, Víctor; Ayora-Cañada, María José; Domínguez-Vidal, AnaComposting olive mill pomace (OMP), the major by-product of the olive oil industry, is an attractive waste management practice in the context of sustainable food production. Thermal treatment of compost at mild temperatures (torrefaction) can aid to improve its characteristics as a soil amendment. This study aims to understand the chemical changes occurring during torrefaction of olive mill pomace-based (OMP) compost, as well as to evaluate the treatment effects on compost at different stages of maturation. Here, treatments at different temperatures (175, 225, and 275 °C) and duration (from 1 to 5 h) have been employed to obtain a sort of torrefied samples. In general, the H/C and O/C atomic ratios of compost samples decreased with torrefaction temperatures, which suggests an incipient coalification of the organic matter. Furthermore, the results showed that a combination of FT-NIR and FT-MIR spectroscopy using a low-level data fusion strategy is very sensitive to the molecular changes occurring both in the composting process and during heating. Principal Component Analysis (PCA) of the merged spectra revealed that the changes at 175 °C are mainly the loss of water (O–H contributions at 3300 and 5169 cm−1) together with the degradation of proteins (observed in the decrease of amide I and II characteristic bands). Furthermore, the samples heated at this temperature can still be differentiated by their initial maturation stage. On the other hand, thermochemical changes occurring at higher temperatures are more intense and make the samples more alike, independently of the composting time. When heating above 225 °C, the loss of O–H happens together with the decrease of aliphatic moieties, reflected in the bands 2920 and 2850 cm−1 (FT-MIR) and 4258, 4323, 5665, and 5781 cm−1 (FT-MIR). This can be attributed to the thermal degradation of cellulosic materials and, additionally, to the degradation of the residual oil in the case of poorly composted samples. Heated samples are characterized by the presence of carbonyl groups (1709 cm−1) and humic-like complex and polymerized aromatic structures (1579 cm−1). Since the characteristics of the torrefied compost at 275 °C are very similar regardless of the initial maturation stage, torrefaction may be a very interesting way to reduce the composting time of olive mill pomace to obtain a high-quality organic amendment for soil application.