Abstract：Bio-Fe/Ce-nanoparticles (Fe/Ce-NPs) prepared from grape-peel-seed extracts, Fe2+ and Ce3+salts, were combined with sodium percarbonate (SPC) for activated sludge conditioning. Under the optimum conditions (molar ratio of iron to cerium 4:1, Fe/Ce-NPS dosage 30mg/g·TSS, SPC dosage 200mg/g·TSS, pH3 and 30min reaction), the specific resistance to filtration (SRF), Time to filtration (TTF) and water content of mud cake was reduced from 9.74×1013m/kg, 92s and 80.5% to 2.67×1013m/kg, 42s and 71.2%, respectively. Then, the water content can be further reduced to 65.8% with the combination of polyacrylamide (PAM). When at initial pH 6, the pH value of sludge after conditioning is 7.1 (free from subsequent adjusting pH to neutral), and the conditioned sludge still maintain good dewaterability. During the Fenton-like reaction (Fe/Ce-NPs+SPC), electron transfer between Fe and Ce promoted the production of · OH greatly (0.9 times higher than the traditional Fenton reaction) and reduced the absolute value of Zeta potential drastically (from -17.5mV of raw sludge to -4.6mV after pretreatment). Three-dimensional fluorescence spectrum (3D-EEM) and FTIR characterization showed that Fe/Ce-NPs+SPC oxidation could interrupt the hydrogen bonds maintaining α- Helical and change the conformation of the secondary structure of extracellular protein, causing the looser protein structure, the more bound water in the sludge flocs releasing. Compared with Fenton systems (Fe2+/H2O2) and (Fe2+/SPC), sludge dewaterability could be improved distinctly by Fenton-like system (Fe/Ce-NPs+SPC), especially conditioning sludge at near-neutral pH 6 with great reduction of acid-base dosage. Hence, Fe/Ce-NPs+SPC would be a new eco-friendly, efficient and practical technology for enhancing sludge dewaterability.
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