Three-dimensional observation of porous materials prepared from iron tailings and their pore wall site adsorption function

Abstract

Porous materials are widely used to treat phosphorus-containing wastewater due to their structural characteristics and loading site functionality. The use of iron tailings as a raw material during the preparation of these materials can effectively reduce production costs. In this study, a porous material was prepared according to a one-step method using solid waste iron tailings. High-temperature phase transition technology was used to construct crystallographic sites on the pore walls of the material to improve the phosphorus removal efficiency. The pore structure, pore wall characteristics, and internal crystal growth in the three-dimensional space of the material were characterized using X-ray microscopy (micro-CT) scanning, and the voxel data for the internal structural were analyzed. The results showed that the material had a clear internal skeletal structure, a uniform distribution of internal pores, and crystal phases in three-dimensional space. The pore ratio in the three-axis direction was greater than 50%, with connected pores accounting for more than 95% of the pores. The wall thickness distribution was uniform, but the pore size distribution and ellipticity ratio varied significantly due to the different pore structures and quantities. A connected structure was formed when the thin walls of adjacent pores ruptured, and there were magnesioferrite and hematite crystal sites with fractal growth in the pore wall framework. The adsorption capacity of the porous material for phosphorus pollutants was investigated using photometry, and the highest removal rate was found to be 68.13%. This analysis suggests that the presence of rough pore walls, a high specific surface area, and crystal sites within the pore walls enhance the adsorption performance of the material. Further research along this line could explore the potential of developing new low-cost materials for pollution treatment.