Abstract

The presence of fine particles has reduced the quality of water resources. Unfortunately, the fine particles normally take a longer time to be removed. Realizing this, the present study aims to employ a magnetic adsorbent to assist a fast separation of the fine particles from their solution. Here, micron-sized SiO₂ particles were used as the model fine particles; meanwhile, the magnetic adsorbent was designed by functionalizing iron oxide nanoparticles (IONPs) with chitosan. A process study was done based on the effects of medium pH, IONPs concentration, and contact time. Results implied that both bare IONPs and chitosan functionalized-IONPs (denoted as CF-IONPs) were best in removing SiO₂ at pH 4 owing to the electrostatic attraction force. However, as compared to the bare counterpart, CF-IONPs is more suitable for large scale application as it is effective in a wider pH range, requires lesser adsorbent dosage and shorter adsorption time. Despite that, removal of SiO₂ using both types of adsorbents were found to follow pseudo-second order kinetic. The obtained data was modeled using either the moving least squares (MLS) or multivariable power least squares (MPLS) method. In particular, the indices of each parameter obtained from the MPLS-generated equation indicated that the most dominant parameter that governing the SiO₂ removal by bare IONPs is medium pH, while the one for CF-IONPs is contact time.

摘要

细颗粒物的存在降低了水资源的质量。不幸的是，细颗粒通常需要更长的时间才能去除。意识到这一点，本研究旨在采用磁性吸附剂来帮助从溶液中快速分离细颗粒。这里，微米尺寸的SiO ₂颗粒用作模型细颗粒；同时，磁性吸附剂是通过用壳聚糖对氧化铁纳米颗粒（IONPs）进行功能化而设计的。基于介质 pH 值、IONP 浓度和接触时间的影响进行了工艺研究。结果表明，裸 IONP 和壳聚糖功能化 IONP（表示为 CF-IONP）在去除 SiO _{2方面效果最好}由于静电引力，在 pH 值为 4 时。然而，与裸对应物相比，CF-IONPs 更适合大规模应用，因为它在更宽的 pH 范围内有效，需要更少的吸附剂用量和更短的吸附时间。尽管如此，发现使用两种类型的吸附剂去除SiO ₂遵循准二级动力学。使用移动最小二乘法 (MLS) 或多变量功率最小二乘法 (MPLS) 方法对获得的数据进行建模。特别是，从 MPLS 生成的方程获得的每个参数的指数表明，控制裸 IONPs 去除 SiO ₂的最主要参数是中等 pH 值，而 CF-IONPs 的主要参数是接触时间。