Fabrication and Characterization of Highly Porous Fe(OH)₃@Cellulose Hybrid Fibers for Effective Removal of Congo Red from Contaminated Water

Research on water purification has recently revolved around nanomaterials because of their large specific surface area. However, there are still some problems associated with the preparation, application, and recovery of nanomaterials. Herein, we report for the first time a novel approach for one-step synthesis of porous hybrid fibers (PHFs), which can be used as an effective adsorbent for dye removal from polluted water. A low-cost biopolymer cellulose was chosen as the matrix of the fibers, whereas a NaOH solution was applied as the coagulation bath for the cellulose spinning dope that contained a certain amount of FeCl₃. The obtained Fe­(OH)₃@Cellulose PHFs exhibited a multiscaled pore structure, with the in situ generated Fe­(OH)₃ nanoparticles uniformly distributed on the regenerated cellulose nanofibrous network of the fibers. These structural attributes are quite advantageous for an efficient adsorbent. The maximum Congo red removal capacity of the Fe­(OH)₃@Cellulose PHFs reached 689.65 mg/g, which was much higher than many early reported values. Importantly, the Fe­(OH)₃@Cellulose PHFs could favorably remove the dye at natural pH through filtration adsorption with excellent reusability. This approach, with the desired characteristics of simplicity, high efficiency, low cost, and being environmentally friendly, demonstrated a great potential for industrial applications.