In this study, the flocculation performance and kinetics of magnetic cationic polyacrylamide (MCPAM) microspheres, compared with cationic polyacrylamide (CPAM), were systematically investigated under different magnetic field strengths. Flocculation performance was observed by jar test experiment. The density of flocs was estimated by the determination of floc settlement velocity and image analysis. The frequency distribution of floc size was measured with a Malvern Mastersizer instrument. When the diatomite suspension was treated by MCPAM and CPAM, the residual diatomite turbidity was 16.28 NTU and 244.13 NTU, respectively. The maximum turbidity removal efficiency of MCPAM was about 99.65% under 1000 Gauss magnetic field, which was higher than that (94.75%) of CPAM. The synergy of gravitational and magnetic fields for MCPAM promoted the formation of larger flocs with higher growth rates compared with CPAM. The effective density range of flocs in the MCPAM flocculation was increased to 10–252 kg m⁻³. The kinetic constants were calculated by monitoring the frequency of floc collisions. The increase of kinetic constant (k) to 25.81 × 10⁻¹¹ s⁻¹ suggested that interaction of contact and collision between magnetic flocs was sufficient. According to the evolution of the size and density of flocs under the synergy of gravitational and magnetic fields, the magnetic flocculation rate equation was derived. The study of magnetic flocculation kinetics can provide theoretical support for magnetic flocculation and is critical for the analysis of solid-liquid separation processes.

中文翻译：

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磁场强度下磁性聚丙烯酰胺微球的絮凝性能和动力学

在这项研究中，系统地研究了在不同磁场强度下，磁性阳离子聚丙烯酰胺（MCPAM）与阳离子聚丙烯酰胺（CPAM）相比的絮凝性能和动力学。通过广口瓶试验实验观察了絮凝性能。通过确定絮凝沉降速度和图像分析来估算絮凝密度。用Malvern Mastersizer仪器测量絮状物尺寸的频率分布。用MCPAM和CPAM处理硅藻土悬浮液时，残留的硅藻土浊度分别为16.28 NTU和244.13 NTU。在1000高斯磁场下，MCPAM的最大混浊去除效率约为99.65％，高于CPAM的最大混浊去除效率（94.75％）。与CPAM相比，MCPAM的重力和磁场协同作用促进了更大絮凝物的形成，并具有更高的生长速率。MCPAM絮凝中絮凝物的有效密度范围增加到10–252 kg m⁻³。通过监测絮状物碰撞的频率来计算动力学常数。动力学常数（k）增加到25.81×10 ^-11  s ^-1，表明磁性絮凝物之间的接触和碰撞相互作用是足够的。根据重力和磁场协同作用下絮凝物的大小和密度的演变，磁絮凝速率方程是派生的。磁性絮凝动力学的研究可以为磁性絮凝提供理论支持，对固液分离过程的分析至关重要。