Browsing by Author "Maceiras, Rocío"

Now showing 1 - 9 of 9
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    Biochar Amendments and Phytoremediation: A Combined Approach for Effective Lead Removal in Shooting Range Soils
    (Toxics, 2024) Maceiras, Rocío; Pérez-Rial, Leticia; Alfonsín, Víctor; Feijoo, Jorge; López, Ignacio
    The increasing contamination of soil with heavy metals poses a problem to environmental sustainability. Among these pollutants, lead is particularly concerning due to its persistence in the environment, with harmful effects on human health and ecosystems. Various strategies that combine phytoremediation techniques with soil amendments have emerged to mitigate lead contamination. In this context, biochar has gained significant attention for its potential to enhance soil quality and remediate metal-contaminated environments. This study aims to investigate the combined effect of biochar amendments on the phytoremediation of lead-contaminated shooting range soils. A series of experiments were conducted to determine the impact of the amount and distribution of biochar on lead removal from soil. Soil samples were incubated with biochar for one week, after which two types of seeds (Brassica rapa and Lolium perenne) were planted. Plant and root lengths, as well as the number of germinated seeds, were measured, and a statistical analysis was conducted to determine the influence of the amendments. After one month, the Pb concentration decreased by more than 70%. Our results demonstrate that seed germination and plant growth were significantly better in soil samples where biochar was mixed rather than applied superficially, with the optimal performance observed at a 10% wt. biochar amendment. Additionally, the combined use of biochar and phytoremediation proved highly effective in immobilizing lead and reducing its bioavailability. These findings suggest that the combination of biochar, particularly when mixed at appropriate concentrations, and Brassica rapa significantly improved lead removal efficiency.
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    Bioethanol production from industrial algae waste
    (Waste management, 2019) Alfonsín, Víctor; Maceiras, Rocío; Gutiérrez, Carlos
    This paper presents a study carried out to determine the feasibility to obtain bioethanol from an industrial algae waste. The influence of some parameters on acid hydrolysis was studied. The results indicated that the overall hydrolysis ability is a function of the combined action of acid concentration, temperature and reaction time. The hydrolysates with higher amount of reducing sugars were used for ethanolic fermentation using S. Cerevisiae. The highest bioethanol yield 11.6 gEtOH/galgae was obtained at 70 min, a sulphuric acid concentration of 9% wt. and acid/dried algae ratio of 7. The present study showed that the industrial waste of Euchema Spinosum contains carbohydrates that can be converted into bioethanol with an efficiency of 75%. Moreover, the potential of the residue after acid hydrolysis process as sustainable solid fuel regarding its properties was analysed. The results were compared with those obtained from the literature and discussed according to international standards.
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    C02 Capture via Adsorption Using Silica Gel
    (European Journal of Sustainable Development, 2024-10-01) Pérez-Rial, Leticia; Alfonsín, Víctor; Maceiras, Rocío; Feijoo, Jorge; Vallejo, Javier P.
    This paper investigates the potential of silica gel as an effective adsorbent for C02 capture. The study explores the adsorption mechanisms, the efficiency of C02 upta.ke, and sorne factors influencing the adsorption capacity of silica gel.The experimental results demonstrate the significant potential of silica gel for C02 adsorption under various conditions. Toe adsorption capacity was found to be highly dependent on parameters such as gas flow rate and the particle size of silica gel. The findings suggest that ,vith optimized conditions, silica gel could be a viable material for reducing atmospheric C02 levels. This research contributes to the development of sustainable and efficient technologies for mitigating climate change through carbon dioxide capture and storage.
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    CO2 Capture via Adsorption Using Silica Gel
    (European Journal of Sustainable Development, 2024) Pérez-Rial, Leticia; Alfonsín, Víctor; Maceiras, Rocío; Feijoo, Jorge; Vallejo, Javier P.
    This paper investigates the potential of silica gel as an effective adsorbent for CO2 capture. The study explores the adsorption mechanisms, the efficiency of CO2 uptake, and some factors influencing the adsorption capacity of silica gel. The experimental results demonstrate the significant potential of silica gel for CO2 adsorption under various conditions. The adsorption capacity was found to be highly dependent on parameters such as gas flow rate and the particle size of silica gel. The findings suggest that with optimized conditions, silica gel could be a viable material for reducing atmospheric CO2 levels. This research contributes to the development of sustainable and efficient technologies for mitigating climate change through carbon dioxide capture and storage.
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    Influence of Activated Carbon Granulometry on H2 Purification in Glycerol Reforming Syngas: Adsorption and Kinetic Analysis
    (Energies, 2024-11-29) Maceiras, Rocío; Feijoo, Jorge; Pérez-Rial, Leticia; Álvarez-Feijoo, Miguel A.; Eslami, Naser
    This study investigates the adsorption performance of granular activated carbon (GAC) and pelletized activated carbon (PAC) for the purification of syngas produced from glycerol reforming, focusing on the removal of CO2, CO, and CH4. The adsorption process was studied at two different flow rates (0.5 L/min and 1 L/min) to assess the impact of particle size and gas flow rate on adsorption capacity. The results indicate that GAC exhibits superior multi-gas adsorption, particularly at lower flow rates, effectively capturing CO2, CO, and CH4, while PAC exhibits lower adsorption performance. Kinetic analysis revealed that the pseudo-second-order and Avrami models fit well with both adsorbents, though GAC aligns more closely with the Avrami model, reflecting its multi-step adsorption mechanism and greater pore diffusion efficiency. These findings highlight the importance of adsorbent size and flow rate in optimizing hydrogen purification processes, with GAC emerging as a highly efficient adsorbent for industrial-scale syngas treatment.
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    Influence of alumina fixed-bed in steam reforming of glycerol for hydrogen production (7th International Conference on Renewable Energy and Conservation, ICREC 2022 November 18–20, 2022, Paris, France)
    (Energy Reports, 2023) Maceiras, Rocío; Feijoo Conde, Jorge; Alfonsín, Víctor; Pérez, Leticia; Álvarez-Feijoo, Miguel A.; Falcón, Pablo; Vallejo, Javier P.
    In this study, hydrogen production by steam reforming was carried out in a tubular fixed-bed reactor. The influence of some operating variables such as temperature, flow rate of the feeding glycerol solution and space velocity on hydrogen production under a non-catalyzed reaction was analyzed. The results showed that the hydrogen yield increased with temperature and decreased with the space velocity. As the feedstock flow rate increased, the hydrogen yield decreased rapidly. Compared with a reference experiment without fixed-bed, the use of non-porous alumina fixed-bed showed better results. Under the best reaction conditions (900 ◦C and a feedstock flow rate of 0.85 g/min), 17 L/h of syngas were obtained, with a purity of about 55% of hydrogen and a production of 2.7 moles of hydrogen by mol of glycerol.
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    Microwave Assisted Alkaline Pretreatment of AlgaeWaste in the Production of Cellulosic Bioethanol
    (Energies, 2021, 14, 5891, 2021) Maceiras, Rocío; Alfonsín, Víctor; Seguí, Luis; González, Juan F.
    Biomass pretreatment has an important role in the production of cellulosic bioethanol. In this study, the effectiveness of microwave assisted alkaline pretreatment of algae waste was analysed. After pretreatment, the product was hydrolysed using sulphuric acid. The effects of microwave power, irradiating time, solid–liquid ratio and NaOH concentration were examined. Under the best conditions, the fermentable sugars were converted to cellulosic bioethanol using Saccharomyces Cerevisiae with a bioethanol yield of 1.93 0.01 g/g and a fermentation efficiency of 40.4%. The reducing sugars concentration was 30% higher than that obtained from conventional hydrolysis without pretreatment. The obtained results suggest that microwave assisted alkaline pretreatment is effective in improving the production of cellulosic bioethanol of algae waste compared to that without microwave effect. Considering energy consumption, low microwave power and short microwave irradiation time are favourable for this pretreatment.
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    Microwave Assisted Alkaline Pretreatment of AlgaeWaste in the Production of Cellulosic Bioethanol
    (Energies, 2021, 14, 5891, 2021-09-17) Maceiras, Rocío; Alfonsín, Víctor; Seguí, Luis; González, Juan F.
    Biomass pretreatment has an important role in the production of cellulosic bioethanol. In this study, the effectiveness of microwave assisted alkaline pretreatment of algae waste was analysed. After pretreatment, the product was hydrolysed using sulphuric acid. The effects of microwave power, irradiating time, solid–liquid ratio and NaOH concentration were examined. Under the best conditions, the fermentable sugars were converted to cellulosic bioethanol using Saccharomyces Cerevisiae with a bioethanol yield of 1.93 0.01 g/g and a fermentation efficiency of 40.4%. The reducing sugars concentration was 30% higher than that obtained from conventional hydrolysis without pretreatment. The obtained results suggest that microwave assisted alkaline pretreatment is effective in improving the production of cellulosic bioethanol of algae waste compared to that without microwave effect. Considering energy consumption, low microwave power and short microwave irradiation time are favourable for this pretreatment.
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    Transforming Wastewater into Biofuel: Nutrient Removal and Biomass Generation with Chlorella vulgaris
    (Energies, 2024-09-30) Salgueiro, José Luis; Pérez-Rial, Leticia; Maceiras, Rocío; Sánchez, Ángel; Cancela, Ángeles
    This study investigates the potential of Chlorella vulgaris for nutrient removal and biomass production in synthetic wastewater. The experiments were conducted in 2 L photobioreactors under controlled aeration, agitation, and lighting conditions for 19 days. Despite a moderate growth rate (0.137 d−1), C. vulgaris achieved efficient pollutant removal, with 97% of nitrate, 90% of nitrite, and 90.6% of COD eliminated. Additionally, the biomass was processed to extract fatty acids, yielding a 20% extraction rate, indicating its potential as a biofuel feedstock. These results demonstrate C. vulgaris’s dual function in wastewater remediation and biofuel production, presenting a sustainable and economically viable approach to addressing environmental challenges.