The enhancement of the colloidal stability of magnetite nanoparticles (MNPs) for environmental-related fields has greatly attracted researchers' attention. This study used a high hydrophilic negatively charged polyelectrolyte, poly(4-styrenesulfonic acid co-maleic acid) sodium (PSAAS), to enhance the colloidal stability of MNPs. Coating of the naked MNPs with PSAAS polyelectrolyte is a simple and rapid method to obtain colloidally stable MNPs while sustaining the chemical reactivity of MNPs in water purification. The prepared PSAAS-coated MNPs were characterized by scanning electron microscope, energy dispersive X-ray, Fourier transform infrared, zeta potential analysis, transmission electron microscope and X-ray diffraction. Moreover, the colloidal stability and adsorption performance tests of these naked MNPs and PSAAS-coated MNPs (with different concentrations of PSAAS coated) were investigated and compared. PSAAS-coated MNPs with 0.001 g/ml PSAAS coating possessed the best colloidal stability and the highest methylene blue (MB) dye removal efficiency (94.53 ± 0.69%). The adsorption isotherm and kinetic studies for the adsorption of MB onto PSAAS-coated MNPs were well-described by the Langmuir model and pseudo-second-order kinetic model. These magnetic adsorbents, with high separation efficiency, simple and low production cost and recyclable property, are promising as practicable adsorbents in water treatment.

中文翻译：

---

高亲水性负电荷聚（4-苯乙烯磺酸共马来酸）钠包覆的胶体稳定磁性纳米粒子的表面合成用于水修复

增强磁铁矿纳米粒子 (MNPs) 的胶体稳定性以用于环境相关领域，极大地吸引了研究人员的关注。本研究使用高亲水性带负电荷的聚电解质聚（4-苯乙烯磺酸共马来酸）钠（PSAAS）来增强 MNP 的胶体稳定性。用 PSAAS 聚电解质涂覆裸 MNPs 是一种简单快速的方法，可以获得胶体稳定的 MNPs，同时维持 MNPs 在水净化中的化学反应性。通过扫描电子显微镜、能量色散X射线、傅里叶变换红外、zeta电位分析、透射电子显微镜和X射线衍射对制备的PSAAS包被的MNPs进行了表征。而且，研究并比较了这些裸MNPs和PSAAS包被的MNPs（具有不同浓度的PSAAS包被）的胶体稳定性和吸附性能测试。具有 0.001 g/ml PSAAS 涂层的 PSAAS 涂层 MNP 具有最佳的胶体稳定性和最高的亚甲蓝 (MB) 染料去除效率 (94.53 ± 0.69%)。Langmuir 模型和伪二级动力学模型很好地描述了 MB 吸附到 PSAAS 涂层 MNP 上的吸附等温线和动力学研究。这些磁性吸附剂具有分离效率高、生产简单、成本低、可回收利用等优点，有望成为水处理中实用的吸附剂。001 g/ml PSAAS 涂层具有最好的胶体稳定性和最高的亚甲蓝 (MB) 染料去除效率 (94.53 ± 0.69%)。Langmuir 模型和伪二级动力学模型很好地描述了 MB 吸附到 PSAAS 涂层 MNP 上的吸附等温线和动力学研究。这些磁性吸附剂具有分离效率高、生产简单、成本低、可回收利用等优点，有望成为水处理中实用的吸附剂。001 g/ml PSAAS 涂层具有最好的胶体稳定性和最高的亚甲蓝 (MB) 染料去除效率 (94.53 ± 0.69%)。Langmuir 模型和伪二级动力学模型很好地描述了 MB 吸附到 PSAAS 涂层 MNP 上的吸附等温线和动力学研究。这些磁性吸附剂具有分离效率高、生产简单、成本低、可回收利用等优点，有望成为水处理中实用的吸附剂。