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 Fe2+/Ce3+ solution synchronously, were combined with H2O2 for simultaneous enhancing sludge dewatering and phosphorus (P) recovery. GFC-NPs/H2O2 (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 & sdot;TSS (total solid sludge), 100 mg H2O2/g & sdot;TSS, and reaction time 30 min. Meanwhile, excellent performances were also exhibited with above 95.9 % of P recovery in all investigated GFC-NPs/H2O2 process. Compared with Fe0/H2O2 or GF-NPs/H2O2, better performances were presented on both sludge dewaterability and P recovery after GFC-NPs/H2O2 pretreatment. The Fe-Ce bimetallic catalysis significantly facilitated & sdot;OH production (0.92 times higher than that of Fe0/H2O2) and P could be recovered in the sludge simultaneously. Under GFC-NPs/H2O2 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/H2O2 oxidation could induce the looser conformation of protein secondary structure and cause the more release of bound water. In summary, GFC-NPs/H2O2 is an eco-friendly and practical technology for enhancing sludge dewaterability and P recovery simultaneously.