Abstract In this study, a novel composite (PAMMS) was prepared using poly (N-isopropylacrylamide) (PNIPAM) as a temperature-responsive polymer, magnetite as a magnetic substance, and amino-functionalized mesoporous silica (MS) as an adsorbent. The temperature-dependence of the physical properties such as methyl orange (MO) adsorption, aggregation/sedimentation, and magnetic separation of this composite was investigated. It was found that the composite consisted of 11.3 wt% magnetite, 0.6 mmol/g amino groups, and 4.6 wt% PNIPAM. The MO adsorption behaviour of the PAMMS composite could be well-explained by the Langmuir model and pseudo-second-order rate equation. At 20 °C (below the lower critical solution temperature (LCST) of PNIPAM), the composite showed an MO adsorption amount of 174 μmol/g, which is slightly larger than that (143 μmol/g) at observed 35 °C (above the LCST of PNIPAM). The optical microscopic observations revealed that the size of the PAMMS aggregates at 45 °C (above LCST) was larger than that at room temperature. Hence, the magnetic separation ratio of PAMMS at 45 °C was higher than that at room temperature. The PAMMS composite showed effective MO adsorption below the LCST of PNIPAM and magnetic separation above the LCST of PNIPAM.

中文翻译：

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温度响应磁性介孔二氧化硅的合成及其物理性质的温度依赖性

摘要 本研究以聚（N-异丙基丙烯酰胺）（PNIPAM）为温度响应聚合物，磁铁矿为磁性物质，氨基功能化介孔二氧化硅（MS）为吸附剂，制备了一种新型复合材料（PAMMS）。研究了该复合材料的物理性质如甲基橙 (MO) 吸附、聚集/沉淀和磁分离的温度依赖性。发现复合材料由 11.3 wt% 的磁铁矿、0.6 mmol/g 的氨基和 4.6 wt% 的 PNIPAM 组成。PAMMS 复合材料的 MO 吸附行为可以通过 Langmuir 模型和伪二阶速率方程很好地解释。在 20 °C（低于 PNIPAM 的下临界溶解温度 (LCST)），复合材料显示出 174 μmol/g 的 MO 吸附量，在观察到的 35°C（高于 PNIPAM 的 LCST）时，它略大于（143 μmol/g）。光学显微镜观察表明，PAMMS 聚集体在 45°C（高于 LCST）时的尺寸大于室温下的尺寸。因此，PAMMS 在 45 °C 时的磁分离率高于室温。PAMMS 复合材料显示出低于 PNIPAM LCST 的有效 MO 吸附和高于 PNIPAM LCST 的磁分离。