Renewable biochar derived from mixed sewage sludge and pine sawdust for carbon dioxide capture. (1st August 2022)

• Record Type: Journal Article
• Authors: Li, Kai; Niu, Xiaojun; Zhang, Dongqing; Guo, Huafang; Zhu, Xifen; Yin, Hua; Lin, Zhang; Fu, Mingli
• Is Part Of: Environmental pollution. Volume 306(2022)
• Publication Date: 2022-08-01
• Subjects: Modified biochar -- CO2 adsorption -- Chemical sorption -- CO2/CH4/N2 selectivity -- Cyclic regeneration; Pollution -- Periodicals; Pollution -- Environmental aspects -- Periodicals; Environmental Pollution -- Periodicals; Pollution -- Périodiques; Pollution -- Aspect de l'environnement -- Périodiques; Pollution -- Effets physiologiques -- Périodiques; Pollution; Pollution -- Environmental aspects; Periodicals; Electronic journals; 363.73
• DOI: 10.1016/j.envpol.2022.119399
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: Carbon dioxide (CO2 ) is the main anthropogenic greenhouse gas contributing to global warming. In this study, a series of KOH-modified biochars derived from feedstock mixtures (i.e., S3W7 biomass consisting of 70% pine sawdust and 30% sewage sludge; S5W5 biomass consisting of 50% pine sawdust and 50% sewage sludge) at different temperature (i.e., 600–800 °C) were prepared for evaluating CO2 adsorption performance. The KOH-activated biochars prepared with S3W7 biomass displayed larger surface areas and micropore volumes compared to those of S5W5 biochars. In particular, the highest CO2 adsorption capacity (177.1 mg/g) was observed on S3W7 biomass at 700 °C (S3W7–700K), due to the largest surface area (2623 m 2 /g) and the highest micropore volume (0.68 cm 3 /g). Furthermore, surface functional groups, hydrophobicity, and aromaticity of biochar and presence of hetero atoms (N) also were actively involved in CO2 adsorption of biochar. In addition, in situ DRIFTS analysis advanced current understanding for the chemical sorption mechanisms by identifying the transformation composites of CO2 on biochars, and characterizing the weakly adsorbed and newly formed mineral species (e.g., carbonates) during the CO2 sorption process. This study may provide an insight into the research of CO2 capture by identifying physical and chemical adsorption, and expand the effective utilization of natural biomass-based biochar for mitigation greenhouse gas emission. Graphical abstract: Image 1 Highlights: Highly porous carbons derived form a mixed biomass of sewage sludge and pine sawdust. S3W7–700K displayed high surface area up to 2623 m 2 /g. S3W7–700K exhibited superior CO2 adsorption capacity (177.1 mg/g). In situ DRIFT spectroscopy revealed the importance of chemical adsorption. It behaves perfect cyclic regeneration performance as high as 92% retention.