Suppression of performance of activated carbon filter due to residual aluminum accumulation

Xin Huang; Mengze Geng; Kaiyun Wang; Yitian He; Guiwei Li; Chenghong Feng; Baoyou Shi

doi:10.1016/j.jhazmat.2022.130637

Suppression of performance of activated carbon filter due to residual aluminum accumulation

J Hazard Mater. 2023 Mar 5:445:130637. doi: 10.1016/j.jhazmat.2022.130637. Epub 2022 Dec 23.

Authors

Xin Huang¹, Mengze Geng¹, Kaiyun Wang¹, Yitian He², Guiwei Li¹, Chenghong Feng³, Baoyou Shi⁴

Affiliations

¹ Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
² Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
³ State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China.
⁴ Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China. Electronic address: byshi@rcees.ac.cn.

PMID: 37056009
DOI: 10.1016/j.jhazmat.2022.130637

Abstract

Extending the lifetime of granular activated carbon (GAC) filters with no significant loss in their effectiveness is a considerable challenge for drinking water supply utilities. However, the effects of residual Al from coagulants on GAC performance are rarely considered. Herein, in-service GAC samples obtained from full-scale water treatment plants were investigated to evaluate the amount of accumulated Al. Although the Al concentration in water was two to three times lower than the Ca concentration, Al exhibited considerable accumulation (second to Ca accumulation) in in-service GAC samples (0.68-8.63 mg g^-1). Surface characterization results indicated that Al accumulation could have been caused by the co-precipitation of Al with Ca and Si to form Ca₄Al₂Si₃O₁₀·H₂O and Ca₄Al₆O₁₂SO₄, self-precipitation or complexion with -OH/-COOH on the GAC or biofilm surfaces. Correlation analysis of the accumulated Al and GAC properties implied that Al accumulation considerably reduced the surface area of GAC by ∼30%. Lab simulation experiments indicated that the removal of dissolved organic matter was reduced by 6-10% when additional Al was loaded. In addition, results showed that the residual Al (up to 200 μg L^-1) considerably affected the extracellular polymeric substance component and microorganism community structure. In summary, strict control of residual Al is beneficial for maintaining the efficacies of GAC and biologically activated carbon.

Keywords: Activated carbon; Adsorption; Biological activity; Coagulation; Residual aluminum.