Mesoporous ball-milling iron-loaded biochar for enhanced sorption of reactive red: Performance and mechanisms. (1st December 2021)

• Record Type: Journal Article
• Authors: Feng, Kanghong; Xu, Zibo; Gao, Bin; Xu, Xiaoyun; Zhao, Ling; Qiu, Hao; Cao, Xinde
• Is Part Of: Environmental pollution. Volume 290(2021)
• Publication Date: 2021-12-01
• Subjects: Anionic dye -- Biochar composite -- Ball-milling -- Fe-loading; 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.2021.117992
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: In order to solve the low sorption capacity of pristine biochar for anionic pollutants, e.g., reactive red 120 (RR120), a novel mesoporous Fe-biochar composite was fabricated in this study by combination of Fe-loading and ball-milling methods. The ball-milling Fe-biochar composite could effectively remove RR120 by up to 90.1 mg g −1 at pH of 7.5, and slightly alkaline condition was preferred. Adsorption kinetics showed that ball-milling Fe-biochar composite could quickly sorb RR120 with the rate constant ( k 2 ) of 2.07 g mg −1 min −1 (pH = 7.5). Positive surface charge and large surface area were responsible for the outstanding removal performance of RR120 by ball-milling Fe-biochar composite: (1) The adscititious Fe would be converted to β-FeOOH during pyrolysis, which significantly improved the zeta potential of biochar and thus facilitated the electrostatic adsorption for RR120, which contributed to 42.3% and 85.5% at pH of 3 and 7.5, respectively; (2) Ball-milling effectively increased the specific surface area and uniformed the pore size distribution, which could provide more sorption sites and expedite the diffusion of RR120 molecules, shortening the time from several hours to less than 15 min. Findings of this study not only provide a feasible modification method for biochar to adsorb anionic pollutants efficiently and rapidly, but also help to reveal the roles of Fe-loading and ball-milling in enhancing adsorption capacity. Graphical abstract: Image 1 Highlights: A novel biochar composite was fabricated for efficient reactive red adsorption. Fe loading and ball milling exhibited synergistic effect in biochar for adsorption. Fe loading promoted electrostatic adsorption by increasing the zeta potential. Ball milling provided more sorption sites by forming mesoporous structure.