Synthesis of magnetic nanoparticle into bacterial cellulose matrix by ammonia gas-enhancing in situ co-precipitation method

In this study, magnetically responsive bacterial cellulose sheets were prepared by using an ammonia gas-enhancing in situ co-precipitation method operated in a closed system without oxygen. Instead of using the traditional concentrated liquid basic solutions, ammonia gas was used in the closed system to achieve the homogeneous dispersion of magnetic nanoparticles as evidence by the uniform black color of magnetic nanoparticles across the cross-sectional area of bacterial cellulose sheets. In addition, under the condition without oxygen, the synthesized magnetic would be in the form of magnetite (Fe3O4). The formation of magnetic nanoparticles inside bacterial cellulose sheets was investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy dispersive X-ray (EDX). The average particle size of the magnetic nanoparticles was determined by using transmission electron microscopy (TEM) and was found to be in the range of 19.6–38.9 nm. The homogeneous dispersion of magnetic nanoparticles across the cross-sectional area of the bacterial cellulose samples was also evidenced by SEM and TEM images. Moreover, the magnetic field responsive behavior of the magnetic nanoparticle-incorporated bacterial cellulose sheets was investigated by vibrating sample magnetometry (VSM). The saturation magnetization of the magnetic nanoparticle-incorporated bacterial cellulose sheets ranged from 1.92 to 26.20 emu/g at 300 K and ranged from 2.96 to 28.10 emu/g at 100 K.