Preparation and regeneration of iron-modified nanofibres for low-concentration phosphorus-containing wastewater treatment

In this study, nanocellulose (CNFs) was prepared by a mechanical shearing method, a simple and pollution-free process. Iron hydroxide was loaded on nanocellulose, a natural macromolecule derived from bamboo, to produce the second-generation iron-loaded nanocellulose for the removal of low-concentration phosphorus from wastewater. We found that the best modified ferric salt was ferric chloride. When the mass ratio of Fe(OH) 3 and CNFs was 1.5 : 1, freeze-drying with liquid nitrogen yielded the best adsorption performance. The adsorption process of Fe(OH) 3 @CNFs followed the pseudo-second-order kinetics and belonged to chemical adsorption. Regeneration experiments showed that after 10 cycles of adsorption–regenerations of the adsorbent, the phosphorus adsorption efficiency was still stable at 80% of the initial material. The prepared adsorbent was characterized by the BET surface area measurement, scanning electron microscopy and FT-IR. The surface morphology, pore size and elements of materials before and after iron loading were analysed. Compared with other adsorbents, the phosphorus removal performances of the second-generation iron-loaded nanocellulose were superior. Compared with the first-generation material, the second-generation adsorbent is simpler and more environmentally friendly.