In this study, the dispersion stability of superparamagnetic iron oxide nanoparticles (IONPs) under high salinity was investigated. In our previous study, the stable dispersion of IONPs in 5 wt% NaCl solution was achieved under neutral and basic conditions through the functionalization of IONPs using sulfonated phenolic resin (SPR). However, under acidic conditions, the SPR shell dissociated from the IONP surface, resulting in the loss of dispersion stability. To overcome this limitation, crosslinking with polyvinyl alcohol (PVA) was implemented. The sulfonate groups in the SPR and hydroxyl groups in PVA can form a bond by removing water and consequently a crosslinked structure is formed between SPR and PVA. The stability of the dispersion was evaluated using visual observation of sedimentation and size measurements of the sample for a week. It was found that the dispersion was highly stable in brine, containing up to 10 wt% NaCl, at pH 4. The shell/core structure of the highly crosslinked SPR-PVA was verified using EDS mapping of the S elements in the SPR-IONP sample. The change in the shell structure through the crosslink reaction was characterized using thermogravimetric analysis and Fourier transform infrared spectroscopy.

在这项研究中，研究了高盐度下超顺磁性氧化铁纳米粒子（IONPs）的分散稳定性。在我们先前的研究中，通过使用磺化酚醛树脂（SPR）对IONP进行功能化，在中性和碱性条件下实现了IONP在5 wt％NaCl溶液中的稳定分散。然而，在酸性条件下，SPR壳从IONP表面解离，导致分散稳定性的损失。为了克服该限制，实施了与聚乙烯醇（PVA）的交联。SPR中的磺酸盐基团和PVA中的羟基可通过除去水形成键，因此在SPR和PVA之间形成了交联结构。使用肉眼观察沉淀和一周尺寸的样品来评估分散体的稳定性。发现分散体在pH值为4的盐水中高度稳定，盐水中含高达10 wt％的NaCl。使用EDS绘制SPR-IONP中S元素的图谱，验证了高度交联的SPR-PVA的壳/核结构。样品。通过热重分析和傅立叶变换红外光谱表征了通过交联反应的壳结构变化。