Facile Synthesis, Characterization of Poly-2-mercapto-1,3,4-thiadiazole Nanoparticles for Rapid Removal of Mercury and Silver Ions from Aqueous Solutions

Abstract

Abstract:Industrial pollution by heavy metal ions such as Hg 2+ and Ag + is a universal problem owing to the toxicity of heavy metals. In this study, a novel nano-adsorbent, i.e., poly-2-mercapto-1,3,4-thiadiazole (PTT), was synthesized and used to selectively adsorb mercury and silver ions from aqueous solutions. PTT nanoparticles were synthesized via chemical oxidative dehydrogenation polymerization under mild conditions. Oxidant species, medium, monomer concentration, oxidant/monomer molar ratio, and polymerization temperature were optimized to obtain optimum yields. The molecular structure and morphology of the nanoparticles were analyzed by ultraviolet-visible (UV-Vis), Fourier transform infrared (FT-IR), matrix-assisted laser desorption/ionization/time-of-flight (MALDI/TOF) mass and X-ray photoelectron (XPS) spectroscopies, wide-angle X-ray diffraction (WAXD), theoretical calculations and transmission electron microscopy (TEM), respectively. It was found that the polymerization of 2-mercapto-1,3,4-thiodiazole occurs through head-to-tail coupling between the S(2) and C(5) positions. The PTT nanoparticles having a peculiar synergic combination of four kinds of active groups, S-, -SH, N-N, and =N-with a small particle size of 30-200 nm exhibit ultrarapid initial adsorption rates of 1500 mg(Hg)·g −1 ·h −1 and 5364 mg(Ag)·g −1 ·h −1 and high adsorption capacities of up to 186.9 mg(Hg)·g −1 and 193.1 mg(Ag)·g −1 , becoming ultrafast chelate nanosorbents with high adsorption capacities. Kinetic study indicates that the adsorption of Hg 2+ and Ag + follows the pseudo-second-order model, suggesting a chemical adsorption as the rate-limiting step during the adsorption process. The Hg 2+ and Ag + -loaded PTT nanoparticles could be effectively regenerated with 0.1 mol·L −1 EDTA or 1 mol·L −1 HNO 3 without significantly losing their adsorption capacities even after five adsorption-desorption cycles. With these impressive properties, PTT nanoparticles are very promising materials in the fields of water-treatment and precious metals recovery.

Achieving strong, stable, and durable underwater adhesives based on a simple and generic amino-acid-resembling design

“…S6, ESI †). 54,55 To further gain insights into the underwater adhesion behavior of AARA, we then measured the lap-shear adhesion strength of AARA with varying AMTD/GP molar ratios and immersion time periods (selected steel and wood substrates as examples). As shown in Fig.…”

Fabrication of Cotton Linter-Based Adsorbents by Radiation Grafting Polymerization for Humic Acid Removal from Aqueous Solution

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Synthetic Methodologies for Chelating Polymer Ligands: Recent Advances and Future Development

“…Thiophene monomers with meso ‐tetraphenyl‐Pp fragments, where Pp is porphyrin, bound through alkyl spacers, as well as meso ‐3,5‐ di‐tert ‐butyl‐tetraphenyl‐Pp fragments bound to tetra (ethylene glycol) spacers, were copolymerized in the presence of 3‐dodecylthiophene using FeCl 3 as an oxidizer . A nano‐adsorbent, poly‐2‐mercapto‐1,3,4‐thiadiazole, was obtained by chemical oxidative dehydrogenation polymerization under mild conditions for the selective adsorption of mercury and silver ions from aqueous solutions …”