Search

We demonstrate a new material by intercalating Mo3S132− into Mg/Al layered double hydroxide (abbr. Mo3S13‐LDH), exhibiting excellent capture capability for toxic Hg2+ and noble metal silver (Ag). The as‐prepared Mo3S13‐LDH displays ultra‐high selectivity of Ag+, Hg2+ and Cu2+ in the presence of various competitive ions, with the order of Ag+>Hg2+>Cu2+>Pb2+≥Co2+, Ni2+, Zn2+, Cd2+. For Ag+ and Hg2+, extremely fast adsorption rates (≈90 % within 10 min, >99 % in 1 h) are observed. Much high selectivity is present for Ag+ and Cu2+, especially for trace amounts of Ag+ (≈1 ppm), achieving a large separation factor (SFAg/Cu) of ≈8000 at the large Cu/Ag ratio of 520. The overwhelming adsorption capacities for Ag+ (qmAg=1073 mg g−1) and Hg2+ (qmHg=594 mg g−1) place the Mo3S13‐LDH at the top of performing sorbent materials. Most importantly, Mo3S13‐LDH captures Ag+ via two paths: a) formation of Ag2S due to Ag‐S complexation and precipitation, and b) reduction of Ag+ to metallic silver (Ag0). The Mo3S13‐LDH is a promising material to extract low‐grade silver from copper‐rich minerals and trap highly toxic Hg2+ from polluted water. [ABSTRACT FROM AUTHOR]

Abstract: The new material polypyrrole/MoS42−(MoS4‐Ppy), prepared by ion‐exchange of NO3‐ of NO3‐Ppy with MoS42−, displays high acid stability and excellent uptake for heavy metal ions such as Hg2+, Ag+, Cu2+, and Pb2+. The different maximum adsorption capacities (qm) for Cu2+, Pb2+, Hg2+, and Ag+ depend on the various binding modes arising from the different thiophilicity of these metal ions. The removals of Ag+ and Pb2+ reach >99.6% within 5 min, and for highly toxic Hg2+, >98% removal achieves at 1 min. At strong acid limit, the exceptional qm(Ag+) of 725 mg g−1 places the MoS4‐Ppy at the top of materials for such removal. Uptake kinetics of Ag+, Hg2+, and Pb2+ is extremely fast: >99.9% removal rates at wide pH range (0.5–6) within 1–5 min. Also, at strongly acidic conditions (pH ≈ 1), for highly toxic Hg2+, <2 ppb concentration can be achieved, accepted as safe limit. The MoS4‐Ppy demonstrates an outstanding ability to separate low‐concentrated Ag+ from high concentrated Cu2+ especially under strong acidic conditions (pH ≈ 1), showing a large separation factor SFAg/Cu (KdAg/KdCu) of 105 (>100). MoS4‐Ppy is a superior and novel sorbent material for water remediation applications as well as precious metals recovery. [ABSTRACT FROM AUTHOR]

• Highly efficient phosphorus removal over a wide pH range. • Adsorption properties of different materials evaluated by partition coefficient. • Excellent adsorption performance at low phosphate concentrations. Herein, we explored the modification of wheat straw biochar with chitosan, quaternary ammonium salt, and lanthanum for enhanced phosphate removal in environmentally relevant conditions. Specifically, a new amine protected cross-linking method was utilized to modify the absorbent material for maximum adsorption capacity, reaching 109 ± 4 mg P g−1. The high phosphate removal performance of the composite was not significantly affected in a broad range of temperature (15–45 °C) and pH (2.5–7). 30 min allowed reaching a 100% adsorption equilibrium for 100 mg P L−1, and 93% for 25 mg P L−1, thus, significantly reducing the treatment time compared to previous reports. The highest partition coefficient 172.1 mg g−1 μM−1 was obtained at a concentration of 25 mg L−1, and the phosphorus removal rate was as high as 99.98%, indicating La/GTB have great adsorption performance at low phosphate concentration. The adsorption mechanisms of the composite are extensively described, where electrostatic interaction, ligand exchange, and Lewis acid-base interaction contribute to the process. All of the above-mentioned advantages make the prepared composite of great interest for the development of materials for on-site phosphate removal. [ABSTRACT FROM AUTHOR]