Removal of nitrate and simultaneous hydrogen generation through photocatalytic reforming of glycerol over “in situ” prepared zero-valent nano copper/P25

- Simultaneous nitrate reduction and hydrogen generation is achieved by photocatalysis.
- The photocatalyst is prepared “in situ” by copper photodeposition on P25.
- Glycerol is used as organic scavenger for photogenerated holes.
- The catalyst exhibits high activity in the removal of nitrate ions.
- The system follows a first-order kinetic law at low concentration of nitrate.

The photocatalytic reduction of nitrate to nitrogen and the simultaneous production of hydrogen was investigated over copper loaded titania (P25) nanoparticles using glycerol as sacrificial agent and UV-A/Vis radiation. The experiments demonstrated that total nitrogen (i.e., nitrate, nitrite, and ammonia) removal efficiencies over 93% were achieved for initial nitrate concentrations up to 150 mg/l. A parallel hydrogen production up to 14 μM was recorded. Hydrogen generation was affected by nitrate reduction. The reaction rates were dependent on pH and both glycerol and nitrate starting concentrations in the mixture. However, a linear model can be used to describe the process for low concentration of nitrate and constant pH. The system showed a remarkable photoefficiency in decontamination of nitrate-containing solutions and concomitant hydrogen evolution. This study lays the foundation for the future development of numerical models able to predict the chemical behavior of simultaneous proton and nitrate reduction over solar photocatalytic reforming of organics.

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