Simultaneous enhancement of sludge dewaterability and phosphorus recovery by Fenton-like process with in-situ synthesized green iron-cerium particles

Green Fe-Ce nanoparticles (GFC-NPs) synthesized in-situ by adding grape-seed extracts and Fe 2+ /Ce 3+ solution synchronously, were combined with H 2 O 2 for simultaneous enhancing sludge dewatering and phosphorus (P) recovery. GFC-NPs/H 2 O 2 (Fe/Ce molar ratio of 4:1) was demonstrated as a novel and efficient pretreatment even at pH 6.8 (without adjustment), where the values of specific resistance to filtration, Time to filtration and water content of mud cake were respectively decreased by 74.9 %, 47.0 % and 12.8 % under the optimal conditions of 30 mg (Fe+Ce) /g·TSS (total solid sludge), 100 mg H 2 O 2 /g·TSS, and reaction time 30 min. Meanwhile, excellent performances were also exhibited with above 95.9 % of P recovery in all investigated GFC-NPs/H 2 O 2 process. Compared with Fe 0 /H 2 O 2 or GF-NPs/H 2 O 2 , better performances were presented on both sludge dewaterability and P recovery after GFC-NPs/H 2 O 2 pretreatment. The Fe-Ce bimetallic catalysis significantly facilitated ·OH production (0.92 times higher than that of Fe 0 /H 2 O 2 ) and P could be recovered in the sludge simultaneously. Under GFC-NPs/H 2 O 2 oxidation, the larger reduction of PN and PS was examined in the LB-EPS and TB-EPS, as well as sludge particle size and the absolute value of zeta potential. Further analysis verified that GFC-NPs/H 2 O 2 oxidation could induce the looser conformation of protein secondary structure and cause the more release of bound water. In summary, GFC-NPs/H 2 O 2 is an eco-friendly and practical technology for enhancing sludge dewaterability and P recovery simultaneously.