María de los Milagros Ballari , Miroslava Filip Edelmannová , Rudolf Ricka , Martin Reli , Kamila Kočí
{"title":"Exploring kinetics and mass transfer in photocatalytic CO2 reduction: Impact of photocatalyst loading and stirrer speed","authors":"María de los Milagros Ballari , Miroslava Filip Edelmannová , Rudolf Ricka , Martin Reli , Kamila Kočí","doi":"10.1016/j.ecmx.2024.100651","DOIUrl":null,"url":null,"abstract":"<div><p>CO<sub>2</sub> photocatalytic reduction is a potential and promising technology to reduce the level of the greenhouse gas in the atmosphere but also as an alternative and renewable fuel resource. However, the products yield of the reaction is still low and the identification of the optimal operating conditions that affect the process are still needed to be determined. This study investigates the impact of key operational parameters, specifically photocatalyst concentration and stirring speed, on the photocatalytic reduction of CO<sub>2</sub> in a slurry batch photoreactor utilizing synthesized TiO<sub>2</sub>. A simplified photocatalytic kinetic model, incorporating the radiation field within the photoreactor, was developed, considering mass transfer from liquid to gas phase for the primary detected reaction products (CO, CH<sub>4</sub>, and H<sub>2</sub>). The proposed models elucidate the influence of different operating conditions on product yields. Stirring speed, controlled by a magnetic stirrer, impacts the gas–liquid mass transfer rate. Increased liquid phase stirring speed ensures faster species transport to the gas phase, with a diminishing effect beyond 900 rpm. TiO<sub>2</sub> photocatalyst mass concentration influences the available total active surface and irradiation absorbance in the photoreactor volume. Optimal product yields were observed at the lowest tested photocatalyst concentration (0.5 g · L<sup>-1</sup>), indicating improved irradiation distribution and reduced particle agglomeration, resulting in higher available active surface for the reaction. The calculation model successfully predicted product yields even with lower photocatalyst concentration of 0.25 g · L<sup>-1</sup>, with marginal increases in predicted yields. These findings provide valuable insights for scaling up and optimizing the CO<sub>2</sub> photocatalytic reduction process, offering a foundation for future research.</p></div>","PeriodicalId":37131,"journal":{"name":"Energy Conversion and Management-X","volume":null,"pages":null},"PeriodicalIF":7.1000,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590174524001296/pdfft?md5=75c613beaec141ae4abc4c1cf80b0327&pid=1-s2.0-S2590174524001296-main.pdf","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Energy Conversion and Management-X","FirstCategoryId":"1085","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S2590174524001296","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ENERGY & FUELS","Score":null,"Total":0}
引用次数: 0
Abstract
CO2 photocatalytic reduction is a potential and promising technology to reduce the level of the greenhouse gas in the atmosphere but also as an alternative and renewable fuel resource. However, the products yield of the reaction is still low and the identification of the optimal operating conditions that affect the process are still needed to be determined. This study investigates the impact of key operational parameters, specifically photocatalyst concentration and stirring speed, on the photocatalytic reduction of CO2 in a slurry batch photoreactor utilizing synthesized TiO2. A simplified photocatalytic kinetic model, incorporating the radiation field within the photoreactor, was developed, considering mass transfer from liquid to gas phase for the primary detected reaction products (CO, CH4, and H2). The proposed models elucidate the influence of different operating conditions on product yields. Stirring speed, controlled by a magnetic stirrer, impacts the gas–liquid mass transfer rate. Increased liquid phase stirring speed ensures faster species transport to the gas phase, with a diminishing effect beyond 900 rpm. TiO2 photocatalyst mass concentration influences the available total active surface and irradiation absorbance in the photoreactor volume. Optimal product yields were observed at the lowest tested photocatalyst concentration (0.5 g · L-1), indicating improved irradiation distribution and reduced particle agglomeration, resulting in higher available active surface for the reaction. The calculation model successfully predicted product yields even with lower photocatalyst concentration of 0.25 g · L-1, with marginal increases in predicted yields. These findings provide valuable insights for scaling up and optimizing the CO2 photocatalytic reduction process, offering a foundation for future research.
期刊介绍:
Energy Conversion and Management: X is the open access extension of the reputable journal Energy Conversion and Management, serving as a platform for interdisciplinary research on a wide array of critical energy subjects. The journal is dedicated to publishing original contributions and in-depth technical review articles that present groundbreaking research on topics spanning energy generation, utilization, conversion, storage, transmission, conservation, management, and sustainability.
The scope of Energy Conversion and Management: X encompasses various forms of energy, including mechanical, thermal, nuclear, chemical, electromagnetic, magnetic, and electric energy. It addresses all known energy resources, highlighting both conventional sources like fossil fuels and nuclear power, as well as renewable resources such as solar, biomass, hydro, wind, geothermal, and ocean energy.