Photocatalytic Reduction of Nitroaromatic Compounds Using NiO-Modified MgAl Hydrotalcite: A Sustainable Approach for Wastewater Treatment

Abstract

The growing industrialization has caused the generation of highly toxic compounds such as nitroaromatic compounds. An adequate treatment to reduce the contamination of these organic compounds is necessary. The photocatalytic reduction of aromatic compounds using semiconductor materials favors the production of nitroaromatics. In the present work, NiO materials supported on MgAl hydrotalcite and with different NiO content (1 wt.%, 3 wt.%, 5 wt.%, and 10 wt.%) were synthesized by the coprecipitation method. The materials were characterized and evaluated in the photocatalytic reduction of 2,4-dinitrophenol (2,4-DNP) and 2,4,6-trinitrophenol (2,4,6-TNP). The characterization results revealed the formation of lamellar solids with features typical of layered double hydroxides. The photocatalytic evaluation showed that the NiO/MgAl 1 wt.% photocatalyst is efficient in the reduction of 2,4-DNP and 2,4,6-TNP. Furthermore, it was demonstrated that the reduction of 2,4-DNP is higher than 2,4,6-TNP. Additionally, it was verified that the photocatalytic reduction reaction proceeds via the photogenerated electrons, confirming the key role of the material in driving the reduction process.