Effects of graphite particles/Fe³⁺ on the properties of anoxic activated sludge

In order to improve the sludge flocculation, the combination of graphite particles/Fe³⁺ was used to change the sludge properties and accelerate the electron transfer rate. The effects of Fe³⁺ on the properties of graphite particles were investigated and the synergistic effects of graphite particles/Fe³⁺ on the sludge properties were analyzed using N₂-adsorption/desorption, scanning electron microscopy-X-ray energy dispersive analysis (SEM-EDX), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The results showed that the operation time affected the specific surface area and pore size of graphite particles. The addition of Fe³⁺ reduced the specific surface area and increased the pore size of graphite particles, but it did not change the crystal structure of the graphite particles and the group structure of the sludge. Under the function of graphite particles/Fe³⁺, Zeta potential were improved and the relative hydrophobicity of the sludge was weakened. The contact angle was slightly lowered and flocculation ability (FA) was increased. Therefore, graphite particles/Fe³⁺ played an important role in the charge transfer and bioflocculation improvement.