Department of Polymer Materials and Engineering, College of Materials and Metallurgy, Guizhou University, Guiyang, 550025, China.
Department of Polymer Materials and Engineering, College of Materials and Metallurgy, Guizhou University, Guiyang, 550025, China.
Chemosphere. 2022 Sep;303(Pt 1):135083. doi: 10.1016/j.chemosphere.2022.135083. Epub 2022 May 23.
Organic phenolic pollutants in industrial wastewater cause severe environmental pollution and physiological damage. Poly (N-isopropylacrylamide) (PNIPAM) hydrogels generally have poor mechanical strength and are also intrinsically frangible, limiting their widespread applications in wastewater treatment. Combining them with 2-dimensional materials can also only improve the mechanical properties of hydrogels. Here, we report a high-strength, chemical stability and strong adsorption MXene/poly (N-isopropylacrylamide) (PNIPAM) thermosensitive composite hydrogel for efficient removal of phenolic pollutants from industrial wastewater. Ionic liquids (ILs) were grafted onto the surface of MXenes and introduced into NIPAM monomer solution to obtain composite hydrogels by in-situ polymerization for improved mechanical strength and adsorption capacity of the composite hydrogel. Compared with the MXene/PNIPAM composite hydrogel, the introduction of ILs simultaneously improves the mechanical and adsorption properties of the composite hydrogel. The ILs bind to the surface of MXene flakes through electrostatic interactions, which improved the thermal stability and oxidation resistance of MXenes while maintaining its good dispersion. Using 1-Ethyl-3-methylimidazolium tetrafluoroborate (EMIMBF4) modified MXene (MXene-EMIMBF4) did not change significantly were observed after aging for 45 days. As-prepared composite hydrogels demonstrated excellent mechanical properties, reusability, and high adsorption capacity for p-Nitrophenol (4-NP). The MXene-EMIMBF4/PNIPAM hydrogel could recover after ten 95% strain compression cycles under the synergistic effect of chemical bonding and electrostatic attraction. Its maximum adsorption capacity for 4-NP was 200.29 mg g at room temperature, and the adsorption capacity maintained at ∼90% of its initial value after five adsorption cycles, which was related to the introduction of EMIMBF4 to form a denser network structure. The adsorption data followed the pseudo-second-order kinetics and Freundlich models.
工业废水中的有机酚类污染物会造成严重的环境污染和生理损伤。聚（N-异丙基丙烯酰胺）（PNIPAM）水凝胶通常机械强度较差，而且本质上易碎，限制了其在废水处理中的广泛应用。将其与二维材料结合也只能提高水凝胶的机械性能。在这里，我们报告了一种高强度、化学稳定性和强吸附性的 MXene/聚（N-异丙基丙烯酰胺）（PNIPAM）热敏复合水凝胶，可有效去除工业废水中的酚类污染物。离子液体（ILs）接枝到 MXenes 表面，并引入 NIPAM 单体溶液中，通过原位聚合得到复合水凝胶，以提高复合水凝胶的机械强度和吸附能力。与 MXene/PNIPAM 复合水凝胶相比，ILs 的引入同时提高了复合水凝胶的机械和吸附性能。ILs 通过静电相互作用结合到 MXene 薄片表面，提高了 MXenes 的热稳定性和抗氧化性，同时保持了其良好的分散性。使用 1-乙基-3-甲基咪唑四氟硼酸盐（EMIMBF4）改性 MXene（MXene-EMIMBF4）后，经过 45 天老化，发现其没有明显变化。所制备的复合水凝胶表现出优异的力学性能、可重复使用性和对对硝基苯酚（4-NP）的高吸附能力。在化学键合和静电吸引的协同作用下，MXene-EMIMBF4/PNIPAM 水凝胶在经过十次 95%应变压缩循环后可以恢复。其在室温下对 4-NP 的最大吸附容量为 200.29mg g，经过五次吸附循环后，其吸附容量保持在初始值的约 90%，这与 EMIMBF4 的引入形成更致密的网络结构有关。吸附数据符合准二级动力学和 Freundlich 模型。
