Bipyridine-Containing Polysulfide Materials for Broad-Spectrum Removal of Heavy Metals from Water

Abstract

Heavy-metal pollution is a serious environmental problem. The development of an adsorbent with the ability to bind a diverse range of toxic metal ions would make the water purification process more economically efficient. Various polysulfide materials have been reported to capture mercury efficiently, but there have been relatively few studies on the potential of these materials to bind other toxic metals at the same time. In this work, bipyridine-containing polysulfides have been synthesized for the first time by inverse vulcanization between elemental sulfur and a dioleyl bipyridine (DOBP) derivative. The incorporation of the bipyridine motif into polysulfide copolymer was verified through characterization via NMR, Fourier transform infrared (FT-IR), and Raman spectroscopy techniques. In addition, a facile and inexpensive method for creating microporous structures in polysulfide materials has been developed using sodium bicarbonate as the CO 2 -foaming agent. The developed foaming protocol provided a weakly basic solution during the salt-leaching step that caused partial ester hydrolysis of the DOBP component in poly(S 40 -r-DOBP 60 ) and conveniently installed additional alcohol and carboxylic acid groups in the polysulfide, confirmed by the presence of a broad O−H stretch in the corresponding FT-IR spectra. The metal adsorption experiment of bicarbonate-foamed poly(S 40 -r-DOBP 60 ) with a multielement solution indicated 82−100% removal of 11 toxic metal ions

Utilizing Reclaimed Petroleum Waste to Synthesize Water-Soluble Polysulfides for Selective Heavy Metal Binding and Detection

“…To create more available metal binding sites, various methods to increase the surface area of IVPs have been investigated. Higher porosity has been obtained through the use of supercritical CO 2 , the production of CO 2 in situ, the incorporation of NaCl during synthesis, ,,, carbonization, , and electrospinning. , All of these processes increased the polymer surface area, which led to increased metal uptake when compared to the unaltered polymers. ,,, Further details on how altering the surface area can specifically impact mercury binding have been expanded upon elsewhere . Without a highly porous material, these polymers, have very limited interactions with water and the metal ions dissolved within.…”

Recent advances in the ring-opening polymerization of sulfur-containing monomers

“…to remove heavy-metals from water. 153 However, high reaction temperatures (typically 160-200 °C) are required for this transformation, generating polymeric products with irregular structures and poor solubility.…”

A comparison of adhesive polysulfides initiated by garlic essential oil and elemental sulfur to create recyclable adhesives

“…8 This method expanded rapidly due to the synthetic ease, scalable synthesis, and adherence to many of the principles of green chemistry due to sulfur acting as the solvent, initiator, and monomer, yielding high atom economy and limiting waste production. 9 Inverse vulcanization has been used to create materials for a wide range of applications including cathodes, 8,10,11 infrared optics, [12][13][14] and water purification, [15][16][17][18][19][20][21] among others. [22][23][24][25][26][27][28] In a prior report we described the first adhesives formed by inverse vulcanization by combining elemental sulfur with garlic essential oil (GEO).…”