Fabrication of cobalt-iron Prussian blue analogues functionalized hybrid membranes for efficiently capturing Tl from water: Performance and mechanism.

As trace levels of thallium (Tl) in water are lethal to humans and ecosystems, it is essential to exploit advanced technologies for efficient Tl removal. In response to this concern, an innovative composite membrane was developed, incorporating polytetrafluoroethylene (PTFE) and featuring a dual-support system with polydopamine (PDA) and polyethyleneimine (PEI), along with bimetallic Prussian blue analogues (Co@Fe-PBAs) as co-supports. The composite membrane exhibited an exceptional Tl+-adsorption capacity (qm) of 186.1 mg g-1 when utilized for the treatment of water containing low concentration of Tl+ (0.5 mg⋅L-1). Transmission electron microscopy displayed the obvious Tl+ mapping inside the special hollow Co@Fe-PBAs crystals, demonstrating the deep intercalation of Tl+ via ion exchange and diffusion. The Tl+-adsorption capability of the composite membrane was not greatly affected by coexisting Na+, Ca2+ and Mg2+ as well as the tricky K+, indicating the excellent anti-interference. Co-doped PBAs enhanced ion exchange and intercalation of the composite membrane with Tl+ leading to excellent Tl+ removal efficiency. The composite membrane could efficiently remove Tl+ from thallium-contaminated river water to meet the USEPA standard. This study provides a cost-effective membrane-based solution for efficient Tl+ removal from Tl+-containing wastewater.

Enhanced removal of trace thallium by photo-promoted adsorption using Prussian blue@filter papers: Performance and mechanistic insights.

Developing highly efficient adsorbents for the removal of trace thallium(I) (Tl+) is crucial for addressing environmental challenges. In this study, we successfully synthesized cubic Prussian blue (PB) loading on filter papers using an intermediate layer (dopamine/polyethyleneimine) via in-situ methods. The as-prepared PB-modified FP demonstrated outstanding anti-interference properties and light-enhanced adsorption performance for Tl+ (0.5 mg/L) under ultraviolet (UV) irradiation, exhibiting twice the effectiveness compared to dark conditions, even in acidic and coexisting ionic environments. This indicated its suitability for treating complex Tl+-contaminated water. Notably, the removal efficiency for trace Tl+ was almost 100%, with a maximum experimental adsorption capacity of 86.2 mg/g after 1-h photo-promoted adsorption under 365 nm UV. Characterization results supported a proposed photo-driven redox mechanism that elucidated the interaction between Tl+ and PB-modified FP. Specifically, the accelerated Fe(III) to Fe(II) redox reaction facilitated Tl+ accommodation on the surface and/or lattice of PB, enhancing Tl+ adsorption by compensating for missed positive charges. This study provides valuable insights into utilizing PB-based materials to enhance the photo-enhanced Tl+ adsorption capacity in a cost-effective, easy-to-synthesize, and environmentally friendly manner.