Abstract
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•Application of supported ironporphyrin as a biomimic catalyst on anaerobic hydrolysis of excess sludge.•This supported biomimic catalysts exhibited a remarkable performance in the promotion of sludge anaerobic hydrolysis.•The supported biomimic catalysts have a certain acid-alkali tolerance compared with bio-enzyme.•The supported biomimic catalysts can re-use for many times.
In this research, a feasible strategy for promoting activated sludge anaerobic hydrolysis is presented. Application of supported ironporphyrin as a biomimic catalyst on anaerobic hydrolysis of excess sludge was explored. The magnetic Fe3O4 nanoparticles (Fe3O4-NPs) modified by ironporphyrin were further synthesized by a silanation method and were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR). The results indicated that this supported biomimic catalyst exhibited a remarkable performance in the promotion of sludge hydrolysis. Under optimal conditions, the ratio of SCOD/TCOD and VSS reduction increased from initial 13.2% and 17.0% (control test) to 25.7% and 35.3%, respectively. Furthermore, the concentration of NH4+-N and reducing sugar were respectively increased by 76.7% and 39.2% compared with the control test. The results showed that the hydrolysis of excess sludge in the presence of biomimic catalysts at near-neutral pH values were more efficient than those of performed at alkaline and acidic pH ranges. The recycle studies showed that biomimic catalysts could be re-used for several times without any significant changes in the catalytic capacity.