沼渣生物炭改性零价铁界面结构在调控硝基苯还原效率中的主导作用OA

To address key limitations such as ease of passivation and low electron utilization efficiency in zero-valent iron(ZVI)during the reductive removal of nitrobenzene(NB)from water,iron/carbon composites(BM-Fe/DBC)were prepared via ball milling using anaerobic digestion residue biochar as a carrier.These materials were systematically compared with physically mixed counterparts(PM-Fe/DBC).The results indicated that ball milling facilitated the tight embedding of ZVI particles into the carbon matrix,forming a strongly coupled interface with Fe-C chemical bonds,thereby constructing an efficient electron-transfer pathway.This structure significantly enhanced the micro-galvanic cell effect between iron and carbon,leading to excellent reductive performance over a wide pH range(3～9).Under optimal conditions(Fe:C mass ratio 2:1,dosage 1.0 g·L−1,pH 5),BM-Fe/DBC achieved a NB removal efficiency of 79.9％,and the yield of its reduction product aniline was 1.85 times higher than that of PM-Fe/DBC.Mechanistic investigations demonstrated that the tightly coupled Fe-C interface effectively promoted the sustained corrosion of ZVI while substantially enhancing the generation of indirect reducing species such as adsorbed Fe(Ⅱ)and atomic hydrogen(H*).Electrochemical analysis further revealed that BM-Fe/DBC exhibited a lower corrosion potential,higher corrosion current density(approximately 2.15-fold increase),and lower charge-transfer resistance,kinetically confirming its superior electron-transfer capability.This study highlighted that constructing strongly interface-coupled iron/carbon composites via mechanochemical processing can effectively overcome the key limitations of ZVI in reduction reactions,providing an important theoretical basis and practical pathway for designing high-performance water treatment materials.