The preparation of Co-doped magnetite ferrofluids from natural sand was developed using a double-layer technique. The Co-doped magnetite nanoparticles formed a spinel phase with lattice parameters in the range of 8.355–8.422 Å and tended to agglomerate with the particle sizes of 7–12 nm. The presence of the first and second layers from oleic acid and DMSO was detected by the infrared spectrum as well as the olive oil used as a carrier liquid. The saturation magnetization of the superparamagnetic samples decreased from 24.4 to 4.8 emu/g with decreasing Co²⁺ composition. The particle size and electrostatic forces between the magnetic particles and the microbes played an essential role in inhibiting microbial growth. Interestingly, the increasing Co²⁺ composition enhanced the superior performance of the ferrofluids against E. coli, S. aureus, B. subtilis, and C. albicans. With additional extensive investigation, we believe that the prepared Co-doped magnetite double-layered ferrofluids from natural sand with superior antimicrobial performance can be new significant antimicrobial agents.

使用双层技术开发了从天然沙中制备钴掺杂磁铁矿铁磁流体的方法。Co 掺杂的磁铁矿纳米颗粒形成晶格参数在 8.355–8.422 Å 范围内的尖晶石相，并倾向于以 7–12 nm 的粒径聚集。通过红外光谱以及用作载液的橄榄油检测到来自油酸和 DMSO 的第一层和第二层的存在。随着 Co ²⁺成分的减少，超顺磁性样品的饱和磁化强度从 24.4 下降到 4.8 emu/g。磁性颗粒与微生物之间的粒径和静电力在抑制微生物生长方面起着至关重要的作用。有趣的是，不断增加的 Co ²⁺组合物增强了铁磁流体对大肠杆菌、金黄色葡萄球菌、枯草芽孢杆菌和白色念珠菌的卓越性能。通过进一步的广泛研究，我们相信从天然沙中制备的具有优异抗菌性能的钴掺杂磁铁矿双层铁磁流体可以成为新型重要的抗菌剂。