Department of Applied Quantum Physics and Nuclear Engineering, Graduate School of Engineering, Kyushu University, Fukuoka, Japan.
Department of Applied Quantum Physics and Nuclear Engineering, Faculty of Engineering, Kyushu University, Fukuoka, Japan.
PLoS One. 2024 Mar 1;19(3):e0298047. doi: 10.1371/journal.pone.0298047. eCollection 2024.
In this study, we explored the effective capture of both cations and anions onto a single adsorbent. Acrylamide (AAm) served as the polymer backbone, onto which co-monomers sodium p-styrenesulfonate (SS) and N,N-dimethylaminopropyl acrylamide (DMAPAA) were grafted, creating ionized polymer hydrogel adsorbents. These adsorbents were engineered for the synergistic separation and recovery of heavy metal cations and anions from concentrated solutions, focusing specifically on industrially significant ions such as Ni2+-, Cu2+, Zn2+ and (Cr2O7)2-. The adsorption and desorption behaviors of the AAm terpolymer hydrogels were investigated across various pH solutions, considering the competition and concentrations of these specific metal ions. Moreover, the study delved into the effects of the internal pH environment within the hydrogel adsorbents, determining its impact on the type of metal adsorbed and the adsorption capacity. Our findings indicated that the adsorption of cations was enhanced with a higher proportion of SS relative to DMAPAA in the hydrogel. In contrast, significant anion capture occurred when the concentration of DMAPAA exceeded that of SS. However, equal ratios of SS and DMAPAA led to a noticeable reduction in the adsorption of both types of substrates, attributed to the counteractive nature of these co-monomers. To enhance the adsorption efficiency, it may be necessary to consider methods for micro-scale separation of the two types of monomers. Additionally, the adsorption capacity was observed to be directly proportional to the swelling capacity of the hydrogels. For complete desorption and separation of the cations and anions from the adsorbent, the application of concentrated NaOH solutions followed by HNO3 was found to be essential. Given the varying concentrations of cation and anion pollutants, often present in heavy metal factory effluents, it is crucial to fine-tune the ratios of DMAPAA and SS during the synthesis process. This adjustment ensures optimized efficiency in the decontamination and recovery of these significant heavy metal ions.
在这项研究中，我们探索了将阳离子和阴离子同时有效捕获到单个吸附剂上。丙烯酰胺（AAm）作为聚合物主链，其上接枝共聚单体为对苯乙烯磺酸钠（SS）和 N,N-二甲基丙烯酰胺（DMAPAA），形成离子化聚合物水凝胶吸附剂。这些吸附剂是专门设计用于协同分离和回收浓缩溶液中的重金属阳离子和阴离子，重点关注工业上重要的离子，如 Ni2+、Cu2+、Zn2+和（Cr2O7）2-。在各种 pH 溶液中研究了 AAm 三元共聚物水凝胶的吸附和解吸行为，考虑了这些特定金属离子的竞争和浓度。此外，研究还深入探讨了水凝胶吸附剂内部 pH 环境的影响，确定其对吸附金属的类型和吸附容量的影响。研究结果表明，在水凝胶中 SS 相对于 DMAPAA 的比例较高时，阳离子的吸附增强。相比之下，当 DMAPAA 的浓度超过 SS 时，阴离子的捕获显著增加。然而，当 SS 和 DMAPAA 的比例相等时，两种类型的底物的吸附都会明显减少，这归因于这两种共聚单体的拮抗性质。为了提高吸附效率，可能需要考虑将这两种类型的单体进行微尺度分离的方法。此外，吸附容量与水凝胶的溶胀能力成正比。为了从吸附剂上完全解吸和分离阳离子和阴离子，发现必须使用浓 NaOH 溶液然后用 HNO3。由于重金属工厂废水中经常存在阳离子和阴离子污染物的不同浓度，因此在合成过程中精细调整 DMAPAA 和 SS 的比例至关重要。这种调整确保了这些重要重金属离子的净化和回收的效率优化。
