Photocatalytic Treatment of Olive Oil Mill Wastewater Using TiO2 and Fe2O3 Nanomaterials

Nogueira, V.; Lopes, I.; Rocha-Santos, T. A. P.; Gonçalves, F.; Duarte, A. C.; Pereira, R.

Photocatalytic Treatment of Olive Oil Mill Wastewater Using TiO2 and Fe2O3 Nanomaterials

2016

The olive oil industry produces a highly complex wastewater, known as olive oil mill wastewater (OOMW), which represents a relevant environmental problem for the Mediterranean region. Several physicochemical, biological and combined treatments have been tested to deal with this industrial externality but none was totally effective in reducing its toxicity for species inhabiting the receiving freshwater systems. Within this framework, nanotechnology appears as a promising research area, offering new approaches for the treatment of wastewaters based on the enhanced physical and chemical properties of nanomaterials (NMs). In this context, this work aimed to investigate the treatability of OOMW through several treatments involving advanced oxidation processes plus the use of two nanomaterials as catalysts (UV/H₂O₂, UV/TiO₂, UV/Fe₂O₃, UV/TiO₂/H₂O₂ and UV/Fe₂O₃/H₂O₂). The concentrations of the catalyst and of the oxidant agent were also investigated. The results obtained showed that photodegradation treatments combining TiO₂ or Fe₂O₃ NMs with H₂O₂ were the most efficient. Regarding the OOMW toxicity to Vibrio fischeri, it was significantly reduced with the following treatments: UV/TiO₂/H₂O₂ and UV/Fe₂O₃/H₂O₂. However, the highest reduction recorded for this parameter was obtained in the treatment with UV/H₂O₂. The use of NMs combined with H₂O₂ showed a great potential for removing phenols from OOMW, which have been pointed out as the major toxic compounds of this wastewater.

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