An Expansion of Ferrate Treatment Technology Domain for Se(IV) and Se(VI) Removal from Aqueous Medium

The current study aims to broaden the application domain of ferrate as an oxidant, coagulant, and adsorbent by removing selenite [Se(IV)] and selenate [Se(VI)] from selenium-contaminated waters using potassium ferrate (K2FeO4). The effect of pH and ferrate concentration on the removal of selenium ions has been discussed. The results show that the removal of Se(IV) and Se(VI) is highly pH dependent, with decreasing the pH value (below 5) significantly increasing the removal efficiency for both ions. An increase in ferrate dosage significantly improves selenate and selenite removal efficiency. Using the ferrate ion dosage of 12 mg/L and at pH 2, over 90% of both selenium ions were removed. Both selenite and selenate follow the Langmuir isotherm model during adsorption on the ferrate surface.