No abstract

The pollutants in the excessive discharge of industrial and daily wastewater, which contain multiple metal ions and anions, will cause irreversible damage to the environment and human body. However, current adsorbents only possess adsorption ability toward single type of ion, thus greatly limiting the adsorption efficiency. In this work, we prepared thiol functionalized poly(di(4-vinylpyridine)-zinc chloride-co-divinylbenzene) (Poly-(ZnVP 2 -co-DVB)-SH) with a semicoordinated structure, coordinated/covalent hybridized skeletons, and thiol functional groups via a coordination-polymerization method. On the basis of the radical polymerization, we developed an in situ and facile method to graft Poly(ZnVP 2co-DVB)-SH on polyurethane foam (PU). Due to the semicoordinated structure and thiol groups, the composited foam demonstrated the adsorption capacity toward different ions (Pb 2+ , Cu 2+ , and PO 4 3−). The saturated adsorption capacity of the composited foam toward Pb 2+ , Cu 2+ , and PO 4 3− can reach to at 228.4, 91.3, and 160.1 mg•g −1 , respectively. The adsorption capacity of PO 4 3− is appreciably higher than that of the phosphate adsorbents except the biochars. Adsorption mechanism investigation reveals that the adsorption ability toward multiple ions is arising from multiple interaction, including the coordination centers exchange, thiol-lead reaction, anion exchange, and direct reaction between pyridine-phosphate. The foam can be recycled at least three times. Besides, it shows removal percentages for Pb 2+ , Cu 2+ , and PO 4 3− in real urban wastewater. Overall, the modified foam demonstrates a high and multifunctional performance, which is potentially used for water treatment.

The application of most current phosphate adsorbents is limited by their high cost, low removal capacity, difficulty of recovery, and short lifetime. In this study, we developed a gas−liquid reaction assisted by a coordination method to prepare highly positively charged ferroferric oxide (Fe 3 O 4 ) nanoparticles loaded on polyurethane sponge. It was found that the gas−liquid reaction drastically decreases the size and increases the loading capacity of Fe 3 O 4 nanoparticles as compared with the conventional liquid method. Further, the use of trimethylamine vapor induced the coordination of Fe 3+ , facilitated the formation of free Cl ions, and inhibited the hydrolysis of Fe−Cl bonds, thus greatly decreasing the amount of hydroxyl groups and increasing the surface positive charge on Fe 3 O 4 nanoparticles. As a result, the Fe 3 O 4 nanoparticles in this study have a saturated PO 4 3− adsorption capacity of 229.8 mg•g −1 , which was appreciably higher than that of conventional Fe 3 O 4 adsorbents (57.8 mg•g −1 ). Our study further revealed that the introduction of a thin layer of polyurethane coating on the surface of Fe 3 O 4 nanoparticle-composited adsorbents could drastically improve their stability while preserving the adsorption capacity under the impact of water (500 rpm stirring for 72 h). The composited adsorbents also preserve the adsorption capacity after recycling three times. Finally, the adsorption experiment on real river wastewater indicated that the composited adsorbents enable the decrease of phosphate concentration from 0.6 to 0.02 ppm, reflecting the application potential for relieving phosphate pollution in neutral waters.