Controlled synthesis of innovative carbon-based CaO2 materials with boosted oxygen release performance in the aqueous environment
Journal of Environmental Chemical Engineering
School of Science
Ministry of Science and Technology of China (2018YFE0183600)
National Nature Science Foundation of China (52106251)
National Key Research and Development Program of China (2021YFC1808903)
Natural Science Foundation of Jiangsu Province (BK20200792)
CaO2 has been widely used as an oxygen-releasing material in bioremediation to improve the aerobe activity, but conventional encapsulation methods are difficult to control the oxygen-releasing rate and realize the full conversion of CaO2. In this work, innovative biochar-loaded CaO2 was prepared by an in-situ precipitation method. The biochars were modified using base-/acid-treatment to establish the relationship between the biochar properties and the oxygen releasing performance. Results indicated that increasing the oxygen content of biochars from 11% to 12% to ∼20% caused a significant rise in CaO2 loading amount from ∼6 wt% to 13–14 wt%. The biochar with an average pore size equivalent to CaO2 nanoparticle sizes (∼12 nm) exhibited the longest oxygen-releasing time of 7.5 d, while the others presented shorter releasing periods of < 2.4 d. Meanwhile, a higher oxygen content of biochar triggered a decrease in the oxygen-releasing amount. Results from bioremediation experiments indicated that when comparing with the pure CaO2 material, the optimized loading material (CaO2 @BC800) nearly doubled the amount of bacteria while negligibly changed the pH of solution, giving a significant increase in the removal of diesel oil pollutant. Correspondingly, the in-situ loading on biochar can facilely regulate the oxygen-releasing performance and enhance the removal efficiency of bioremediation.