Phenolic wastewaters depuration by electrochemical oxidation process using Ti/IrO₂ anodes

Area of Science:

• Environmental Chemistry
• Electrochemistry
• Wastewater Treatment

Background:

• Olive oil mill effluent (OMW) poses environmental challenges due to its high phenolic content and chemical oxygen demand (COD).
• Conventional treatment methods may not be sufficient for complete removal of these pollutants.

Purpose of the Study:

• To investigate the electrochemical oxidation (EO) of phenolic wastewater mimicking OMW.
• To optimize EO operating conditions for maximum pollutant removal.
• To assess the impact of treated effluent on neuronal activity and its applicability to real OMW.

Main Methods:

• Electrochemical oxidation in a batch reactor using Ti/IrO2 anodes.
• Varied electrolyte nature (NaCl, Na2SO4), concentration, current density, and initial pH.
• Monitored phenolic content (TPh) and COD removal.
• Assessed effluent toxicity on rat brain slices.
• Treated real OMW under optimized conditions.

Main Results:

• NaCl as electrolyte and higher current density significantly improved EO efficiency.
• Optimal conditions (10 g/L NaCl, 119 mA/cm², pH 3.4) achieved 100% TPh and 84.8% COD removal from synthetic effluent.
• Treated effluent showed reduced, but still significant, impact on neuronal reactive oxygen species (ROS).
• Real OMW treatment yielded 100% TPh and 62.8% COD removal.

Conclusions:

• Electrochemical oxidation is a viable pre-treatment for OMW, effectively reducing phenolic content and COD.
• Optimized EO parameters are crucial for efficient pollutant removal.
• Further investigation into the neurotoxic effects of treated effluent is warranted.