Optimization of phenolic compounds removal from wastewater in electrochemical oxidation process using catalytic anodes and cellulosic separator

Backgrounds & Elimination of phenolic compounds which is considered as resistant pollutants to biological degradation has a great importance. This study aims to investigate the electrochemical oxidation process efficiency in removal of phenol compounds using a continuous and divided rector.
The catalytic anodes of Ti/SnO2-Sb and cathodes of iron were employed in a reactor divided into anolyte and catholyte chambers by a cellulosic separator. The influence of initial phenol concentration (14.12‒40.88 mg L‒1), retention time (32.23‒82.77 min), and current intensity (0.18‒0.42 A) on TPh removal efficiency, TPh residual concentration, and energy consumption was investigated using response surface methodology.
The results showed that TPh removal efficiency strongly depends on retention time, followed by current intensity and initial phenol concentration. The importance order of factors affecting on TPh residual concentration were distinguished as initial TPh concentration > retention time > current intensity. The energy consumption in terms of kWh m‒3 is mostly affected by retention time and then current intensity, and irrespective of initial phenol concentration. Under the optimal conditions, removal efficiency of 93.21%, residual concentration of 1 mg L‒1, and energy consumption of 34.40 kWh m‒3 is achieved.
Based on the obtained results, the electro-oxidation is a very efficient process for diminution of wastewater phenolic content, and is able to set the allowable limits to discharge to the environment.