Experimental Study On Removal Of Fluoride And Sulfapyridine In Groundwater

Fluoride and sulfapyridine are common pollutants in groundwater.At present,fluoride is always removed by adsorption process,which exhibits easy operation and low cost.Comparably,sulfapyridine can be degraded completely by advanced oxidation processes without secondary pollution.However,such adorption or degradation system has some shortcomings such as not high removal efficiency,high cost,difficulty in recycle and reuse,etc.In addition,many heavy metals are often found to be coexistent in groundwater.These effects and associated mechanisms of coexisting heavy metals on the removal of fluoride or sulfapyridine are still need to be elucidated.Hence,the present study mainly focuses on the following aspects:Modification of traditional materials;Evalauation for materials performance on removal of fluoride and sulfapyridine;Eluciation of mechanisms on the effects of coexisting heavy metals.The thesis includes:（1）Magnetic biochar derived waste biomass was synthesized to remove fluoride in groundwater.The effect of Cr（VI）on fluoride removal was evaluated.The mechanism was discussed through multi-characterization of XRD,FT-IR,XPS,and VSM;（2）Kaolinite derived magnetic carbonized Fe₂O₃-SiO₂ nanosheets were prepared to efficiently degrade sulfapyridine by activation of persulfate.The mechanism was elucidated through multi-analysis methods;（3）The effect of different heavy metals on sulfapyridine degradation were explored by goethite/persulfate system.The results showed that:（1）The fluoride adsorption capacity of magnetic biochar is 5.23 mg/g.Coexisting Cr（VI）little impacts the removal of fluoride.（2）The degradation efficiency of sulfadiazine reaches 82.3%by magnetic carbonized SiO₂-Fe₂O₃ nanosheets combining simple magnetic recycle and reuse.（3）Coexisting Pb²⁺or Cd²⁺has a little impact on the degradation of sulfadiazine in weakly alkaline solution by the goethite/persulfate system,while Cu²⁺has an obvious effect on such process.Additionly,the low concentrations of Cu²⁺could enhance the removal efficiency of sulfapyridine during this advanced oxidation processes.