磁絮凝法和高梯度磁流体萃取法集成处理含铬废水

将磁分离技术和化学絮凝法、溶剂萃取法相结合,提出磁絮凝法和高梯度磁流体萃取法集成处理高浓度含Cr电镀废水的新工艺。采用磁絮凝法对高浓度含Cr电镀废水进行一次处理,通过正交实验方法获得了最佳磁絮凝条件:pH 8,磁性Fe3O4颗粒用量4 g,搅拌速度80 r·min-1,主絮凝剂PAFC用量6 ml,可使废水中Cr浓度由4325.13 mg·L-1降为29.8 mg·L-1;采用高梯度磁流体萃取法对磁絮凝后废水进行二次处理,将该废水流经两个串联的高梯度磁流体萃取装置,持续动态萃取7 h,在最佳萃取条件下,最高萃取率为99.40%,平均萃取率98.97%,总萃余液Cr浓度由29.8 mg·L-1降为0.31 mg·L-1,低于国家排放标准;碱性条件下磁流体萃取剂反萃率大于90%,再生磁流体萃取剂可重复使用。

Preparation and surface modification of magnetic poly(methyl methacrylate) microspheres

A novel method for preparation of magnetic polymer microspheres by spraying suspension polymerization (SSP) was developed. Relatively uniform magnetic poly(methyl methacrylate) microspheres were prepared by the spraying suspension polymerization (SSP) using methyl methacrylate (MMA) as monomer, divinylbenzene (DVB) as cross-linking agent, benzoyl peroxide (BPO) as initiator and polyvinyl alcohol (PVA) as stabilizer in the presence of hydrophobic Fe3O4 magnetic fluid. The microspheres prepared were modified by surface chemical reaction. The magnetic properties and morphology of the microspheres were examined by SEM and VSM respectively. The active functional groups of microspheres were examined by infrared spectra. The results showed that microspheres with saturation magnetization of 16.8 emu/g showed distinct superparamagnetic characteristics and the magnetic microspheres with a size of 10 μm were relatively uniform.