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1.
Environ Sci Pollut Res Int ; 31(12): 18765-18784, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38349490

ABSTRACT

In this study, an experimental strategy to obtain biochar and activated carbon from torrefied palm kernel shell as an efficient material for CO2 removal was evaluated. Biochar was obtained by slow pyrolysis of palm kernel shell at different temperatures (350 °C, 550 °C, and 700 °C) and previously torrefied palm kernel shell at different temperatures (220 °C, 250 °C, and 280 °C). Subsequently, activated carbons were prepared by physical activation with CO2 from previously obtained biochar samples. The CO2 adsorption capacity was measured using TGA. The experimental results showed that there is a correlation between the change in the O/C and H/C ratios and the functional groups -OH and C=O observed via FTIR in the obtained char, indicating that both dehydration and deoxygenation reactions occur during torrefaction; this favors the deoxygenation reactions and makes them faster through CO2 liberation during the pyrolysis process. The microporous surface area shows a significant increase with higher pyrolysis temperatures, as a product of the continuous carbonization reactions, allowing more active sites for CO2 removal. Pyrolysis temperature is a key factor in CO2 adsorption capacity, leading to a CO2 adsorption capacity of up to 75 mg/gCO2 for biochar obtained at 700 °C from non-torrefied palm kernel shell (Char700). Activated carbon obtained from torrefied palm kernel shell at 280 °C (T280-CHAR700-AC) exhibited the highest CO2 adsorption capacity (101.9 mg/gCO2). Oxygen-containing functional groups have a direct impact on CO2 adsorption performance due to electron interactions between CO2 and these functional groups. These findings could provide a new experimental approach for obtaining optimal adsorbent materials exclusively derived from thermochemical conversion processes.


Subject(s)
Carbon Dioxide , Charcoal , Charcoal/chemistry , Carbon Dioxide/chemistry , Hot Temperature , Temperature , Adsorption
2.
Sci Total Environ ; 846: 157395, 2022 Nov 10.
Article in English | MEDLINE | ID: mdl-35843337

ABSTRACT

Biogas generation through anaerobic digestion provides an interesting opportunity to valorize some types of animal waste materials whose management is increasingly complicated by legal and environmental restrictions. To successfully expand anaerobic digestion in livestock areas, operational issues such as digestate management must be addressed in an economical and environmentally sustainable way. Biogas upgrading is another necessary stage before intending it to add-value applications. The high concentration of CO2 in biogas results in a reduced caloric value, so the removal of CO2 would be beneficial for most end-users. The current work evaluates the CO2 uptake properties (thermogravimetry study) of low-cost adsorbent materials produced from the animal wastes generated in the livestock area itself, specifically via pyrolysis of poorly biodegradable materials, such as meat and bone meal, and the digestate from manure anaerobic digestion. Therefore, the new element in this study with respect to other studies found in the literature related to biochar-based CO2 adsorption performance is the presence of high content of pyrolyzed proteins in the adsorbent material. In this work, pyrolyzed chars from both meat and bone meal and co-digested manure have been proven to adsorb CO2 reversibly, and also the chars produced from their representative pure proteins (collagen and soybean protein), which were evaluated as model compounds for a better understanding of the individual performance of proteins. The ultra-microporosity developed in the protein chars during pyrolysis seems to be the main explanation for such CO2 uptake capacities, while neither the BET surface area nor N-functionalities on the char surface can properly explain the observed results. Although the CO2 adsorption capacities of these pristine chars (6-41.0 mg CO2/g char) are far away from data of commercially activated carbons (~80 mg CO2/g char), this application opens a new via to integrate and valorize these wastes in the circular economy of the primary sector.


Subject(s)
Carbon Dioxide , Pyrolysis , Adsorption , Animals , Biofuels , Charcoal , Livestock , Manure
3.
Waste Manag ; 59: 211-221, 2017 Jan.
Article in English | MEDLINE | ID: mdl-27843025

ABSTRACT

The management and valorization of residual organic matter, such as sewage sludge and manure, is gaining interest because of the increasing volume of these residues, their localized generation and the related problems. The anaerobic digestion of mixtures of sewage sludge and manure could be performed due to the similarities between both residues. The purpose of this study is to evaluate the feasibility of the co-pyrolysis of sewage sludge (SS) and digested manure (DM) as a potential management technology for these residues. Pyrolysis of a sewage sludge/manure blend (50:50%) was performed at 525°C in a stirred batch reactor under N2 atmosphere. The product yields and some characteristics of the product were analyzed and compared to the results obtained in the pyrolysis of pure residues. Potential synergetic and antagonist effects during the co-pyrolysis process were evaluated. Although sewage sludge and manure seem similar in nature, there are differences in their pyrolysis product properties and distribution due to their distinct ash and organic matter composition. For the co-pyrolysis of SS and DM, the product yields did not show noticeable synergistic effects with the exception of the yields of organic compounds, being slightly higher than the predicted average, and the H2 yield, being lower than expected. Co-pyrolysis of SS and DM could be a feasible management alternative for these residues in locations where both residues are generated, since the benefits and the drawbacks of the co-pyrolysis are similar to those of the pyrolysis of each residue.


Subject(s)
Manure , Sewage/chemistry , Animals , Biofuels/analysis , Bioreactors , Carboxylic Acids/chemistry , Gases , Hot Temperature , Hydrogen/chemistry , Hydrogen-Ion Concentration , Pressure , Spectroscopy, Fourier Transform Infrared , Thermogravimetry
4.
Psicothema (Oviedo) ; 14(1): 34-38, ene. 2002. tab
Article in Es | IBECS | ID: ibc-12659

ABSTRACT

Existen en la literatura psicológica numerosos estudios sobre las características psicológicas necesarias para la obtención de rendimiento deportivo. No obstante, los resultados encontrados no han sido nada claros. Se han planteado críticas a dichas investigaciones a nivel conceptual y metodológico. En el presente estudio se presenta una evaluación de comportamientos deportivos, que en lugar de ser evaluados por los propios deportistas, tal y como se ha hecho mayoritariamente en las investigaciones realizadas, serán evaluados por los propios entrenadores de los deportistas, los cuales trabajan en diferentes niveles de competición. Los resultados indican que no hay diferencias en la valoración realizada por entrenadores de diferente nivel de competición a un listado de comportamientos de jugadores de baloncesto. Han aparecido comportamientos que, según los entrenadores, deberían estar presentes o ausentes en un jugador para obtener rendimiento deportivo. (AU)


Several studies have to tried to assess which psychological characteristics contribute most to peak performance in sports. The results, though, are unclear as conceptual and methodological short-comings of these studies have been pointed out. In this study we apply a different tack: instead of asking the players themselves to rate the psychological traits, as usual, we asked the coaches from different levels of competition to rate kinds of behaviors. The results show that there is agreement on relevant behaviors in basketball players to obtain peak performance and the rank of coaches does not introduce significant differences (AU)


Subject(s)
Female , Male , Humans , Sports/psychology , Adaptation, Psychological , Behavioral Symptoms/diagnosis , Surveys and Questionnaires
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