The Key Laboratory of Water and Sediment Sciences, Ministry of Education, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, PR China.
Department of Advanced Materials and Nanotechnology, College of Engineering, Peking University, Beijing 100871, PR China.
Water Res. 2014 Mar 1;50:124-34. doi: 10.1016/j.watres.2013.11.045. Epub 2013 Dec 10.
Traditional chemical disinfectants are becoming increasingly defective due to the generation of carcinogenic disinfection byproducts and the emergence of antibiotic-resistant bacterial strains. Functionalized magnetic nanoparticles yet have shown great application potentials in water treatment processes especially for bacterial removal. In this study, three types of amino acids (arginine, lysine, and poly-l-lysine) functionalized Fe3O4 nanoparticles (Fe3O4@Arg, Fe3O4@Lys, and Fe3O4@PLL) were prepared through a facile and inexpensive two-step process. The amino acid modified Fe3O4 nanoparticles (Fe3O4@AA) showed rapid and efficient capture and removal properties for both Gram-positive Bacillus subtilis (B. subtilis) and Gram-negative Escherichia coli 15597 (E. coli). For both strains, more than 97% of bacteria (initial concentration of 1.5 × 10(7) CFU mL(-1)) could be captured by all three types of magnetic nanoparticles within 20 min. With E. coli as a model strain, Fe3O4@AA could remove more than 94% of cells from solutions over a broad pH range (from 4 to 10). Solution ionic strength did not affect cell capture efficiency. The co-presence of sulfate and nitrate in solutions did not affect the capture efficiency, whereas, the presence of phosphate and silicate slightly decreased the removal rate. However, around 90% and 80% of cells could be captured by Fe3O4@AA even at 10 mM of silicate and phosphate, respectively. Bacterial capture efficiencies were over 90% and 82% even in the present of 10 mg L(-1) of humic acid and alginate, respectively. Moreover, Fe3O4@AA nanoparticles exhibited good reusability, and greater than 90% of E. coli cells could be captured even in the fifth regeneration cycle. The results showed Fe3O4@AA fabricated in this study have great application potential for bacteria removal from water.
传统的化学消毒剂由于致癌性消毒副产物的产生和抗生素耐药菌株的出现而变得越来越有缺陷。功能化磁性纳米粒子在水处理过程中特别是在细菌去除方面表现出巨大的应用潜力。在这项研究中，通过简便且廉价的两步法制备了三种类型的氨基酸（精氨酸、赖氨酸和聚赖氨酸）功能化的 Fe3O4 纳米粒子（Fe3O4@Arg、Fe3O4@Lys 和 Fe3O4@PLL）。氨基酸修饰的 Fe3O4 纳米粒子（Fe3O4@AA）对革兰氏阳性枯草芽孢杆菌（B. subtilis）和革兰氏阴性大肠杆菌 15597（E. coli）均具有快速、高效的捕获和去除性能。对于两种菌株，在 20 分钟内，所有三种类型的磁性纳米粒子都可以捕获初始浓度为 1.5×10(7)CFU mL(-1)的超过 97%的细菌。以大肠杆菌为模型菌，Fe3O4@AA 可以在较宽的 pH 范围（4 至 10）内从溶液中去除超过 94%的细胞。溶液离子强度不影响细胞捕获效率。溶液中硫酸盐和硝酸盐的共存不影响捕获效率，而磷酸盐和硅酸盐的存在则略微降低了去除率。然而，即使在 10 mM 的硅酸盐和磷酸盐存在下，Fe3O4@AA 仍可以捕获约 90%和 80%的细胞。即使存在 10 mg L(-1)的腐殖酸和藻酸盐，细菌捕获效率仍超过 90%和 82%。此外，Fe3O4@AA 纳米粒子表现出良好的可重复使用性，即使在第五个再生循环中，仍可捕获超过 90%的大肠杆菌细胞。结果表明，本研究中制备的 Fe3O4@AA 具有从水中去除细菌的巨大应用潜力。
