Abstract:

The printing and dyeing wastewater contains many poisonous and harmful substances, such as organic dyes and heavy metals, which has caused serious harm to the ecological environment and human health. Herein, a temperature responsive ultrafiltration membrane was fabricated with PNIPAM@PS spherical polymer brushes. It was prepared and characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), dynamic light scattering (DLS) and the water contact angle experiments. Different nanoparticles, such as methyl blue (MB), rhodamine B (RhB), and the CdSe heavy metal nanoparticles, were filtrated by PNIPAM@PS ultrafiltration membrane. The filtration performance was characterized by ultraviolet spectrophotometer (UV-Vis) and fluorescence spectrophotometer (PL). The rejection rate of this ultrafiltration membrane could be adjusted effectively by the length of PNIPAM chain, the size of PS core and operating pressure and temperature. If the temperature is higher than the lower critical solution temperature (LCST) of PNIPAM, the PNIPAM chains could shrink which induce the larger pore size of PNIPAM@PS ultrafiltration membrane, and vice versa. The pore size adjustability of PNIPAM@PS ultrafiltration membrane has broad application prospects in wastewater treatment.

Key words: spherical polymer brushes, ultrafiltration membrane, filtration performance, dye, heavy metal

摘要：

印染废水中含有大量有机染料和重金属等物质，对生态环境及人类健康产生了严重的危害。以聚（N-异丙基丙烯酰胺）@聚苯乙烯（PNIPAM@PS）球形聚合物刷为主体，Cd（OH）₂纳米线作为牺牲层，聚碳酸酯（PC）膜为支撑层，经简单过滤制备得到对温度有响应性的高分子超滤膜。通过傅里叶变换红外光谱（FT-IR）、扫描电镜（SEM）、动态光散射仪（DLS）及水接触角测量仪对其进行表征，结果表明该超滤膜表面由PNIPAM@PS球形聚合物刷构成，其表面平整，结构规则，且具有良好的温度响应性。随后考察了PNIPAM@PS超滤膜对有机染料（甲基蓝和罗丹明B）和CdSe重金属颗粒的过滤效果，并通过紫外分光光度计（UV-vis）、原子荧光光谱仪（PL）等对其进行表征。结果显示，随着PNIPAM链增长、PS核粒径减小、实验操作压力增大，超滤膜的过滤效果显著改善。同时超滤膜的孔径可以通过温度实时调节，当环境温度高于PNIPAM链的LCST时，超滤膜的孔径较大；温度降低，超滤膜的孔径变小。PNIPAM@PS超滤膜的孔径可调节性使其在废水处理中有着广泛的应用前景。

关键词: 球形聚合物刷, 超滤膜, 过滤性能, 染料, 重金属