摘要
Arsenic(As)detoxification in polluted soils by iron-based materials can be mediated by the endogenous soil organic matter(SOM),nevertheless the mechanisms remain unclear.Herein,endogenous SOM in a paddy soil was substantially removed to understand its roles on As immobilization by biochar-supported zero-valent iron(ZVI/BC).The results demonstrated that ZVI/BC application significantly decreased As bioavailability by 64.2%compared with the control soil under the anaerobic condition.XPS and HR-TEM suggested As immobilization by ZVI/BC mainly invoked the formation of ternary complexes(i.e.,As-Fe-SOM).However,SOM depletion compromised the efficacy of ZVI/BC for As immobilization by 289.8%.This is likely because SOM depletion increased the fulvic acid and OH−contents in soils.Besides,ZVI/BC increased the proportion of As(III)in available As fraction,but SOM depletion altered the mechanisms associated with As(V)reduction.That is,As(V)reduction resulted from the reductive capacity of ZVI in the pristine soil,but the As(V)-reducing bacteria contributed greater to As(V)reduction in the SOM-depleted soil.Additionally,SOM depletion boosted the abundances of Fe(III)-and As(V)-reducing bacteria such as Bacillus and Ammoniphilus in soils,which enhanced the dissimilatory arsenate reduction.Thus,this work highlighted the importance of SOM in the remediation of As-contaminated soils by ZVI/BC.
出处
《Biochar》
CSCD
2024年第1期487-500,共14页
生物炭(英文)
基金
National Natural Science Foundation of China[Grant numbers 42277040,41977117,41977085]
National Key Research and Development Program of China[Grant number 2021YFD1700800]
Qing-Lan Project of Yangzhou University[2020]
High-level Talent Support Plan of Yangzhou University[2019].
