Electrocatalysis coupled heterogeneous electro-Fenton like treatment of coal gasification wastewater using tourmaline as catalyst: process parameters and response surface.

Coal gasification technology is essential for realizing clean and efficient conversion of coal, as well as for reducing carbon emissions. However, coal gasification technology is accompanied by a large amount of coal gasification wastewater that is biodegradable. In this work, tourmaline was applied as a catalyst in electro-Fenton like process for treating coal gasification wastewater. The optimal applied parameters of coal gasification wastewater were investigated as follows: current density of 90 mA cm-2 , tourmaline dosage of 8 g L-1 , electrode gap of 1 cm, and temperature at 25 °C; the COD removal ratio reached 91.24% after 240-min treatment. In addition, the current density and tourmaline dosage were further optimized by response surface method. The result was about current density with 82.4 mA cm-2 and catalyst with 7.57 g L-1 ; the predicted COD removal efficiency was 86.91%. Under the optimal parameters the actual COD removal efficiency was 88.25% a little high than the predicted value. To explore the reusability of tourmaline as Fenton reaction catalyst, five cycles of experiments were carried out. The result demonstrated that tourmaline could be used as catalyst for treating coal gasification wastewater by electro-Fenton like process.