Aiming at the sustainable management of high-moisture Chinese medicine residues (CMR), an alternative way integrating hydrothermal carbonization (HTC), humic acids (HAs) extraction and combustion of remained hydrochar has been proposed in this study. Effect of HTC temperature, HTC duration, and feedwater pH on the mass yield and properties of HAs was examined. The associated formation mechanism of HAs during HTC was proposed. The combustion performance of remained hydrochar after HAs extraction was evaluated. Results show that the positive correlation between hydrochar yield and HAs yield is observed. According to three-dimensional excitation emission matrix (3D EEM) fluorescence intensity, the best quality of HAs is achieved with a yield of 8.17 % at feedwater pH of 13 and HTC temperature of 200 °C. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy analyses show abundant aromatic and aliphatic structure as well as oxygenated functional groups in HAs, which is like commercial HAs (HA-C). Besides, in terms of comprehensive combustion index (CCI), HTC can improve the combustion performance of CMR, while it becomes a bit worse after HAs extraction. Higher weighted mean apparent activation energy (Em) of hydrochar indicating its highly thermal stability. HAs extraction reduces Em and CCI of remained hydrochar. However, it can be regarded a potential renewable energy. This work confirms a more sustainable alternative way for CMR comprehensive utilization in near future.
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http://dx.doi.org/10.1016/j.scitotenv.2024.171792 | DOI Listing |
Cochrane Database Syst Rev
January 2025
Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford, UK.
Background: People from lower socioeconomic groups are more likely to smoke and less likely to succeed in achieving abstinence, making tobacco smoking a leading driver of health inequalities. Contextual factors affecting subpopulations may moderate the efficacy of individual-level smoking cessation interventions. It is not known whether any intervention performs differently across socioeconomically-diverse populations and contexts.
View Article and Find Full Text PDFFlow Turbul Combust
November 2024
Institut de Mécanique des Fluides de Toulouse, IMFT, CNRS, Université de Toulouse, Toulouse, France.
Improving mixing between two coaxial swirled jets is a subject of interest for the development of next generations of fuel injectors. This is particularly crucial for hydrogen injectors, where the separate introduction of fuel and oxidizer is preferred to mitigate the risk of flashback. Raman scattering is used to measure the mean compositions and to examine how mixing between fuel and air streams evolves along the axial direction in the near-field of the injector outlet.
View Article and Find Full Text PDFThis study investigates the effects of varying exhaust gas recirculation (EGR) rates and temperatures on the combustion and emissions characteristics of a compression ignition engine fueled with hydrotreated vegetable oil (HVO). Understanding these effects is essential for optimizing renewable fuel applications in compression ignition engines, contributing to cleaner combustion, and supporting sustainable transportation initiatives. The experiments revealed that increasing the EGR rate to 20% not only reduces NOx emissions by approximately 25% but also increases smoke by around 15%, highlighting a trade-off between NOx and particulate matter control.
View Article and Find Full Text PDFHeliyon
January 2025
Department of Mechanical Engineering, Addis Ababa Science and Technology University, Addis Ababa, 16417, Ethiopia.
Many approaches have been implemented in order to reduce the emissions of particular pollutants without compromising engine performance. Cotton and castor mixed seed oil was chosen for the current study due to their distinct fatty acid composition and potential as a feedstock for bio-additives. Three fuel samples-99 % diesel and 1 % blended fuel (cottonseed oil + castor seed oil), 99.
View Article and Find Full Text PDFHeliyon
January 2025
Department of Chemical Engineering, University of Almería, Carretera de Sacramento s/n 04120 La Cañada de San Urbano, Almería, Spain.
This work studies the influence of flue gas composition, its moisture and ash content, on the efficiency of a CO adsorption/desorption process to capture the CO from flue gases along with its subsequent reuse in greenhouse CO enrichment (Patent ES2514090). The influence of the inlet flow rate, moisture, and ash content were analysed. The experimental conditions were based on those that are achievable under real operating conditions, namely an inlet flow rate from 1.
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