Single/co-adsorption and mechanism of methylene blue and lead by 13-cyclodextrin modified magnetic alginate/biochar

Due to the high biological toxicity, the concurrent elimination of lead (Pb (II)) and methylene blue (MB) has become a challenging problem. Therefore, a newly 13-cyclodextrin (13 -CD) modified magnetic alginate/biochar (13-CD@MBCP) material was developed. Comprehensive characterizations proved the successful coating of 13 -CD onto MBCP surface by microwave-aided fabrication. The 13-CD@MBCP achieved high-efficiency uptake for con-taminants under a wide pH scope. In the dual system, Pb (II) elimination was facilitated with the presence of MB, due to the active sites provided by MB. In the presence of Pb (II), MB uptake was inhibited due to the electrostatic repulsion between positively charged MB and Pb (II). Electrostatic attraction and complexation contributed to capturing Pb (II), while 7C-7C interactions, host-guest effect, and H-bonding were important in MB elimination. After four cycles, 13-CD@MBCP maintained comparatively good renewability. Findings demonstrated that 13-CD@MBCP could be an effective remediation material for Pb (II)/MB adsorption from aqueous environments.

Automated summary

Due to their high biological toxicity, the simultaneous removal of lead (Pb (II)) and methylene blue (MB) is a challenging problem. In this study, a new material called 13-cyclodextrin (13-CD) modified magnetic alginate/biochar (13-CD@MBCP) was developed. The material showed efficient removal of contaminants over a wide pH range. The presence of MB facilitated the elimination of Pb (II), while the presence of Pb (II) inhibited the uptake of MB. The study revealed the important roles of electrostatic attraction, complexation, 7C-7C interactions, host-guest effect, and H-bonding in the removal of both Pb (II) and MB. The 13-CD@MBCP showed good renewability after four cycles, making it a promising remediation material for Pb (II)/MB adsorption in aqueous environments.