Degradation of nitrobenzene in groundwater by nanoscale zero-valent iron particles incorporated inside the channels of SBA-15 rods

• Zero-valent iron nanoparticles were incorporated in the pores of SBA-15.
• NZVIs/SBA-15 efficiently degraded the NB in groundwater.
• Nitrobenzene was reduced to aniline inside the channels of SBA-15.
• Groundwater conditions significantly influenced the behavior of NZVIs/SBA-15.
• The sustained reactivity of NZVIs/SBA-15 was investigated.

Nanoscale zero-valent iron particles (NZVIs) were incorporated inside the channels of SBA-15 rods by a “two solvents” reduction technique. The resulting NZVIs/SBA-15 composites showed superior reduction ability to remove NB from groundwater. Removal efficiency of NB by NZVIs/SBA-15 achieved 97.2% during the initial 15 min. The degradation followed the pseudo-first-order kinetics model. The reaction rate constant increased from 0.043 to 0.215 min−1 upon the decrease of the solution pH from 9.0 to 5.5. NB reduction process mainly proceeded in the pores of SBA-15 rods. An inhibitory effect on NB reduction was observed in the presence of hardness or carbonate. Bicarbonate would be an enhancement at a high concentration during the initial time but an inhibitor as the reaction went on. Humic acid (HA) had little influence on the removal efficiency of NB but would decrease the removal rate. NZVIs/SBA-15 could sustain its reactivity during eight successive degradation cycles.