过硫酸盐缓释材料研发及其对水中环丙沙星的氧化

Controlled-release persulfate material development for ciprofloxacin oxidation in water

为了在一定周期内连续稳定地释放氧化剂,采用环境友好的膨润土和聚乳酸作为原料,通过造粒结合包膜的方法制备了一种新型的过硫酸盐缓释材料(CRPM).研究表明:CRPM的释放规律符合零级动力学特征,表明该材料可稳定释放过硫酸盐.通过改变致孔剂NaCl含量、颗粒尺寸和包膜层数可以调控CRPM的释放速率.该材料的过硫酸盐释放半减期在4~1 613 d,可以满足不同污染修复周期的需求.通过Fe2+活化CRPM降解水中的环丙沙星(CIP),当CIP的浓度较低时,去除率相对较高.5次循环氧化CIP的去除率比较稳定,说明CRPM可以稳定地释放过硫酸盐.通过傅里叶变换衰减全反射红外光谱法和差示扫描量热法表征说明,在氧化过程中聚乳酸包膜层的化学结构和热稳定性并未发生显著变化,具有比较好的稳定性.

In order to make oxidant release continuously and stably in a certain period, a novel controlled-release persulfate material(CRPM) is prepared with environmentally friendly bentonite and polylactic acid as raw materials by a method of granulation and coating. The results show that the release of persulfate in CRPM conforms to the zero-order kinetics, indicating that the material can release persulfate stably. The release rate of CRPM can be regulated by changing the content of porogenic agent NaCl, the particle size and the number of coating layers. The release half-lives of persulfate in CRPM are among 4-1 613 d, which can meet the need of different remediation periods. The ciprofloxacin(CIP) in water is degraded by Fe2+activated CRPM. When the concentration of CIP is at lower level, the removal rate of CIP is relatively higher. The removal rate of CIP is relatively stable after 5 cycles of oxidation, which indicates that CRPM can stably release persulfate. The characterization by Fourier transform attenuated total reflectance infrared spectroscopy and differential scanning calorimetry shows that the chemical structure and thermal stability for the polylactic acid coating do not change significantly during the oxidation process, and have fairly good stability.