Defluorination and regeneration study of lanthanum-doped sewage sludge-based activated carbon. Issue 4 (August 2021)

• Record Type: Journal Article
• Authors: Zhang, Yujian; He, Lizhi; Wang, Guoqiao; Zhang, Xinxin; Liu, Ya; Chen, Yao
• Is Part Of: Journal of environmental chemical engineering. Volume 9:Issue 4(2021)
• Publication Date: 2021-08
• Subjects: Defluorination -- Activated carbon -- Regeneration -- Fluoride -- Lanthanum -- NaOH; Chemical engineering -- Environmental aspects -- Periodicals; Environmental engineering -- Periodicals; Chemical engineering -- Environmental aspects; Environmental engineering; Periodicals; 660.0286
• DOI: 10.1016/j.jece.2021.105740
• Languages: English
• ISSNs: 2213-2929

Abstract

Abstract: Lanthanum-doped sewage sludge-based activated carbon (AC-La), an environment-friendly material, can effectively remove fluoride ions from water. Regeneration performance of AC-La was mainly studied in this work. The results showed that compared to other elution methods, excellent regeneration performance of AC-La was achieved by NaOH. AC-La treated with 0.5 mol/L NaOH showed a high desorption rate (> 98.5%) and fluorine removal efficiency (ca.60%) again. After three NaOH regeneration processes, the regeneration rate of AC-La was stable and higher than 73.8%. Characterization proved that NaOH caused little impact on pore structure and La loading of the carbon, meanwhile, it enhanced ion exchange and electrostatic attraction during F - desorption process. The adsorption/desorption mechanism of F - on AC-La were attributed to physical action (physical adsorption/desorption and electrostatic attraction) and chemical adsorption (inner-sphere complexation, ion exchange and chemical precipitation). Graphical Abstract: ga1 Highlights: Regeneration of AC-La was studied with different methods. After 3 times NaOH desorption, regeneration rate of AC-La was high and stable. NaOH could effectively recover AC-La's adsorptive capacity. Fluorine adsorption was improved by La-doping, and was mainly reversible process. Adsorption/desorption mechanism of F - on AC-La was physical action and chemical adsorption.