Biosynthetic amyloid fibril CsgA-Fe3O4 composites for sustainable removal of heavy metals from water.

[Display omitted] • CsgA–Fe 3 O 4 can remove heavy metals from water at low concentrations. • CsgA–Fe 3 O 4 removed 98.73 %, 98.43 %, and 93.00 % of 1 mg/L Cu2+, Cd2+, and Pb2+. • The adsorption rate remained above 80% after six repeated adsorptions. • The high removal rate (>90 %) of heavy metals in the simulated wastewater. Removal of heavy metals from water has been a hot topic. However, few studies have been conducted for the tricky low concentration range. Experimental designs often have heavy metal concentrations much higher than the actual environmental loading, which leads to poor practical results of adsorbent materials. This study showed that amyloid fiber CsgA-Fe 3 O 4 composites are ideal for the removal of heavy metals from water, especially at low concentrations. We constructed CsgA-Fe 3 O 4 composites by fusing short functional peptides that specifically bind to Fe 3 O 4 magnetic nanoparticles. The CsgA-Fe 3 O 4 composites achieved 98.73 %, 98.43 %, and 93.00 % removal of 1 mg/L Cu2+, Cd2+, and Pb2+, respectively. Moreover, the adsorption rate remained above 80 % after six repeated adsorptions, indicating that CsgA-Fe 3 O 4 was highly reusable. Meanwhile, the high removal rate (>90 %) of heavy metals in the simulated wastewater demonstrated the excellent environmental stability of CsgA-Fe 3 O 4. Finally, by FT-IR and XPS characterization, we found that the adsorption mechanism of CsgA-Fe 3 O 4 is mainly the complexation of surface oxygen-containing functional groups and heavy metal ions. In general, the CsgA-Fe 3 O 4 composite is an efficient, inexpensive, and sustainable adsorption material for mitigating low concentrations of difficult-to-treat heavy metal pollution in water bodies. [ABSTRACT FROM AUTHOR]