Efficient removal of uranium from wastewater using pig manure biochar: Understanding adsorption and binding...

In this work, three kinds of biochars (PMBC-H₂O, PMBC-PP and PMBC-HP) with excellent adsorption performance were obtained by carbonizing pig manure pre-treated with different agents. These biochars had the ordered mesoporous structures and possessed abundant active functional groups on their surface. The adsorption behaviors of the biochars towards U_VI under various conditions were evaluated by batch experiment. The results showed that KMnO₄ and H₂O₂ could enormously improve the adsorption performance of PMBC to U_VI. After KMnO₄ and H₂O₂ pretreatment, the maximum adsorption capacities of PMBC-PP (979.3 mg/g) and PMBC-HP (661.7 mg/g) were about 2.6 and 1.8 times higher than that of PMBC-H₂O (369.9 mg/g), respectively, which was much higher than previously reported biochar-based materials. Obviously, KMnO₄ pretreatment leaded to a higher enhancement than that of H₂O₂. The removal mechanism of U_VI on PMBC-PP was discussed in-depth. The interaction between U_VI species and PMBC-PP was mainly ascribed to the abundant active sites on the surface of PMBC-PP. In a word, conversion of pig manure pre-treated with KMnO₄ into biochar not only demonstrates that PMBC-PP has great potential in the treatment of actual uranium-containing wastewater, but also provides a method for the rational utilization of pig manure to reduce the pollution.