Enhanced sludge dewaterability with sludge-derived biochar activating hydrogen peroxide: Synergism of Fe and Al elements in biochar

TY - JOUR

T1 - Enhanced sludge dewaterability with sludge-derived biochar activating hydrogen peroxide

T2 - Synergism of Fe and Al elements in biochar

AU - Tao, Shuangyi

AU - Liang, Sha

AU - Chen, Ye

AU - Yu, Wenbo

AU - Hou, Huijie

AU - Qiu, Jingjing

AU - Zhu, Yuwei

AU - Xiao, Keke

AU - Hu, Jingping

AU - Liu, Bingchuan

AU - Wang, Yanfei

AU - Yang, Jiakuan

N1 - Publisher Copyright: © 2020 Elsevier Ltd

PY - 2020/9/1

Y1 - 2020/9/1

N2 - Reuse of sludge-derived Fe-rich biochar as sludge conditioner is an attractive route for management of waste activated sludge at source. Homogeneous and heterogeneous Fenton reactions have been proved in sludge conditioning with Fe-rich biochar activating H2O2 to enhance sludge dewaterability. The FeAl2O4 phase in Fe-rich biochar was first identified during pyrolysis of sewage sludge after adding both Fe2O3 and Al2O3, since Fe and Al elements are two of major metal elements in Fe-rich sludge. Compared with the Fe-rich biochar that did not comprise FeAl2O4 phase, the capillary suction time (CST) and specific resistance to filterability (SRF) of the sludge conditioned with the Fe-rich biochar comprising FeAl2O4 phase could be efficiently decreased by 23% and 44%, respectively. The results indicated that FeAl2O4 phase in Fe-rich biochar could improve sludge dewaterability by enhancing heterogeneous Fenton reaction. Synergistic effect between Fe and Al in FeAl2O4 contributed to weak the O–O bond in H2O2 and reduce the activation energy of H2O2 decomposition for enhancing ·OH generation, which could be explained by density functional theory (DFT) calculations for the first time. Thus, the decomposition rate of H2O2 and the amount of ·OH generation were obviously promoted by FeAl2O4 phase in sludge-derived biochar during sludge conditioning, attributing to the destruction of sludge flocs, the release of bound water, and the improvement of sludge dewaterability.

AB - Reuse of sludge-derived Fe-rich biochar as sludge conditioner is an attractive route for management of waste activated sludge at source. Homogeneous and heterogeneous Fenton reactions have been proved in sludge conditioning with Fe-rich biochar activating H2O2 to enhance sludge dewaterability. The FeAl2O4 phase in Fe-rich biochar was first identified during pyrolysis of sewage sludge after adding both Fe2O3 and Al2O3, since Fe and Al elements are two of major metal elements in Fe-rich sludge. Compared with the Fe-rich biochar that did not comprise FeAl2O4 phase, the capillary suction time (CST) and specific resistance to filterability (SRF) of the sludge conditioned with the Fe-rich biochar comprising FeAl2O4 phase could be efficiently decreased by 23% and 44%, respectively. The results indicated that FeAl2O4 phase in Fe-rich biochar could improve sludge dewaterability by enhancing heterogeneous Fenton reaction. Synergistic effect between Fe and Al in FeAl2O4 contributed to weak the O–O bond in H2O2 and reduce the activation energy of H2O2 decomposition for enhancing ·OH generation, which could be explained by density functional theory (DFT) calculations for the first time. Thus, the decomposition rate of H2O2 and the amount of ·OH generation were obviously promoted by FeAl2O4 phase in sludge-derived biochar during sludge conditioning, attributing to the destruction of sludge flocs, the release of bound water, and the improvement of sludge dewaterability.

KW - Extracellular polymeric substances

KW - FeAlO

KW - Heterogeneous Fenton reaction

KW - Sludge biochar

KW - Sludge dewatering

UR - http://www.scopus.com/inward/record.url?scp=85087125515&partnerID=8YFLogxK

U2 - 10.1016/j.watres.2020.115927

DO - 10.1016/j.watres.2020.115927

M3 - 文章

C2 - 32622123

AN - SCOPUS:85087125515

SN - 0043-1354

VL - 182

JO - Water Research

JF - Water Research

M1 - 115927

ER -