Cheap, fast and durable degradation of azo dye wastewater by zero-valent iron structural composites

Insufficient chemical activity of zero-valent iron (ZVI) is the main problem that limits its performance in degrading dyeing wastewater. Currently, the methods of creating acidic reaction condition and reducing the particle size of ZVI are widely used to improve the degradation activity of ZVI. However, they have disadvantages such as high reactor requirements and oxides accumulation. Herein, peculiar porous structural composites constructed with porous ferroalloy supported iron powders were prepared depending on magnetic force, the effects of pH, material structure, and powder size on the degradation performance of iron in Orange II solutions were detailedly investigated. The porous structure endowed the composite materials with greatly enhanced degradation performance, especially in near-neutral and alkaline environments, enable a cheap, fast, and durable degradation. The results show that the compositing porous ferroalloy with iron powder can largely increase the kinetic rate constant by more than 15 times, which is much more advantageous than increasing the specific surface area of the powder or increasing the acidity. This work reveals the determinants that affect the degradation performance of ZVI, and presents an effective method for tuning the properties of magnetic materials using porous structural composites. • Novel porous composites with ferroalloy supported iron particles were prepared. • Structure factor plays a key role in affecting the degradation activity. • The porous composites exhibited high durability in decomposing azo dye. • The present method is much better than traditional methods.