Microalgal-biochar immobilized complex: A novel efficient biosorbent for cadmium removal from aqueous solution

• Published in: Bioresource technology Vol. 244; no. Pt 1; pp. 1031 - 1038
• Main Authors: Shen, Ying, Li, Huan, Zhu, Wenzhe, Ho, Shih-Hsin, Yuan, Wenqiao, Chen, Jianfeng, Xie, Youping
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.11.2017
• Subjects: Adsorption; Biochar; Biosorption; Cadmium; Charcoal; Chlorella; Chlorella sp; Hydrogen-Ion Concentration; Immobilized; Microalgae; Water Purification; Cadmium; Chlorella sp; Biosorption; Immobilized; Biochar
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2017.08.085

Schematic diagram of the adsorption mechanism with three biosorbents, A: Chlorella sp., B: water hyacinth biochar (WHB); C: Microalgal-biochar immobilized complex (MBIC). [Display omitted] •Microalgal-biochar immobilized complex (MBIC) was used for bioremediation of Cd(II).•The surface potential was enhanced by immobilizing the algae to the biochar.•The Cd removability of MBIC was higher than both Chlorella sp. and biochar.•The maximum Cd(II) adsorption capacity of MBIC was 217.41mgg−1. The feasibility of the bioremediation of cadmium (Cd) using microalgal-biochar immobilized complex (MBIC) was investigated. Major operating parameters (e.g., pH, biosorbent dosage, initial Cd(II) concentration and microalgal-biochar ratio) were varied to compare the treatability of viable algae (Chlorella sp.), biochar and MBIC. The biosorption isotherms obtained by using algae or biochar were found to have satisfactory Langmuir predictions, while the best fitting adsorption isotherm model for MBIC was the Sips model. The maximum Cd(II) adsorption capacity of MBIC with a Chlorella sp.: biochar ratio of 2:3 (217.41mgg−1) was higher than that of Chlorella sp. (169.92mgg−1) or biochar (95.82mgg−1) alone. The pseudo-second-order model fitted the biosorption process of MBIC well (R2>0.999). Moreover, zeta potential, SEM and FTIR studies revealed that electrostatic attraction, ion exchange and surface complexation were the main mechanisms responsible for Cd removal when using MBIC.