Cobalt/Iron Bimetallic Biochar Composites for Lead(II) Adsorption: Mechanism and Remediation Performance

Abstract

The performance of nano-zero-valent iron for heavy metal remediation can be enhanced via incorporation into bimetallic carbon composites. However, few economical and green approaches are available for preparing bimetallic composite materials. In this study, novel Co/Fe bimetallic biochar composites (BC@Co/Fe-X, where X = 5 or 10 represents the CoCl2 concentration of 0.05 or 0.1 mol L−1) were prepared for the adsorption of Pb2+. The effect of the concentration of cross-linked metal ions on Pb2+ adsorption was investigated, with the composite prepared using 0.05 mol L−1 Co2+ (BC@Co/Fe-5) exhibiting the highest adsorption performance. Various factors, including the adsorption period, Pb2+ concentration, and pH, affected the adsorption of Pb2+ by BC@Co/Fe-5. Further characterisation of BC@Co/Fe-5 before and after Pb2+ adsorption using methods such as X-ray diffraction and X-ray photoelectron spectroscopy suggested that the Pb2+ adsorption mechanism involved (i) Pb2+ reduction to Pb0 by Co/Fe, (ii) Co/Fe corrosion to generate Fe2+ and fix Pb2+ in the form of PbO, and (iii) Pb2+ adsorption by Co/Fe biochar. Notably, BC@Co/Fe-5 exhibited excellent remediation performance in simulated Pb2+-contaminated water and soil with good recyclability.

Conversion of Phosphogypsum into Porous Calcium Silicate Hydrate for the Removal and Recycling of Pb(II) and Cd(II) from Wastewater

“…To remove Pb(II) and Cd(II) from wastewater, various adsorbents have been developed, including modified biochar, metal–organic frameworks, aerogels, and silicate inorganic materials [ 15 , 16 , 17 , 18 , 19 ]. Among these, calcium silicate hydrate (C-S-H)—a type of silicate inorganic material—possesses a highly developed porous structure, a large specific surface area, the ability to self-release OH − , and is non-toxic and simple to synthesize.…”

Peptides Used for Heavy Metal Remediation: A Promising Approach

“…They can also remove a variety of organic and heavy metal pollutants [ 37 , 38 ]. Nano-scale zero-valent iron (nZVI) is one of the most studied materials for environmental purification [ 39 , 40 ]. It has a small particle size, a large specific surface area, strong adsorption and reduction abilities, high activity, and high pollution reduction ability [ 41 ].…”