Study On Treatment Of Uranium-containting Wasterwater With Acetic-acid And Fe₃O₄ Modified Sludge-based Biochar

Uranium-containing wastewater has radioactive and chemical toxicity,if not properly disposed of,it is easy to lead to a variety of diseases and damage the surrounding ecological environment.In this study,sludge-based biochar?SBB?,acetic-acid modified sludge-based biochar?ASBB?and acetic acid-Fe₃O₄ sludge-based biochar?ASBB-Fe₃O₄?were successfully prepared using excess sludge as raw materials,acetic acid and Fe₃O₄ as modifiers.The effects of SBB and ASBB on the removal of uranium-containing wastewater under different preparation conditions were analyzed by orthogonal experiment and factor experiment.The mechanism of U?VI?removal by ASBB and ASBB-Fe₃O₄ was analyzed by means of aperture analysis,Scanning electron microscope?SEM?,Energy-dispersive X-ray spectroscopy analysis?EDS?,Fourier transform infrared spectroscopy?FTIR?,X-ray photoelectron spectroscopy?XPS?and so on.The main results are as follows:The orthogonal test showed that the mass ratio of sludge to KOH had a significant effect on the preparation of SBB.97.8%of U?VI?could be removed at pH 6.0,initial U?VI?10.0 mg/L,dosage of ASBB was 0.3g/L,adsorption time 5.0 min.When pH value,concentration of U???and dosage of ASBB-Fe₃O₄ were at 5.0,10.0 mg/L,0.3 g/L,respectively,the removal efficiency of U???was more than 98.23%.While improving the separation ability of the material,the removal efficiency of uranium is slightly higher than that of ASBB.The analysis results of BET,SEM,EDS,FTIR and XPS showed that acetic acid can not only increase the surface-to-COOH content of SBB,but also have good reaming effect.Fe₃O₄ uniformly embedded in ASBB surface aperture.The reaction process of ASBB and U?VI?is mainly adsorption binding,no redox reaction.During the reaction of ASBB-Fe₃O₄ and U?VI?,there is a certain amount of U???reduced to U?IV?in addition to the simple adsorption binding.The main reason maybe that Fe?II?in the Fe₃O₄ reduced the U?VI?to U?IV?.The results show that the ASBB and ASBB-Fe₃O₄ prepared using excess sludge as raw material and acetic acid and Fe₃O₄ as modified materials have good adsorption effect on U?VI?,and at the same time,the pollution of uranium-containing wastewater and the recycling of sludge are solved efficiently.The materials mentioned above have good practical Practical and economic values.