Preparation Of TiO₂ Modified Biochar And Study On Norfloxacin Removal Performance

Norfloxacin,as a commonly used typical antibiotic,can effectively inhibit the growth and reproduction of pathogenic bacteria,but it is easy to remain in the environment,which will cause harm to the ecology and human health.This project uses straw biochar as a carrier,prepares TiO₂ modified biochar composite material by sol-gel method.Combined with a variety of characterization methods,the adsorption and photocatalytic degradation removal behavior of norfloxacin（NOR）was studied.The intermediate products of norfloxacin photocatalytic degradation were analyzed,and the degradation path and removal mechanism were discussed.The main findings are as follows:（1）Preparation of TiO₂-BC adsorbent material,the amorphous TiO₂ was combined with biochar（BC）to improve the adsorption capacity of NOR.The experimental study found that the adsorption kinetics of norfloxacin by TiO₂-BC conforms to Elovich model,and the isothermal adsorption conforms to Langmuir model.Under weak acidic conditions,the adsorption of norfloxacin by TiO₂-BC was easier,and the adsorption reaction was a spontaneous exothermic reaction.The adsorption capacity of norfloxacin by TiO₂-BC with higher specific surface area was about 3 times that of BC.（2）Prepared doped TiO₂/BC composite materials,compared the effects of biochar addition amount,calcination temperature,application process and element doping modification on the performance of adsorption-photocatalytic degradation of NOR by composite materials.The results showed that La-TiO₂/BC prepared under 400℃temperature calcination had strong adsorption and photocatalytic degradation ability for NOR,the doping of TiO₂ with La element could effectively improve the response of the material to visible light.La-TiO₂/BC had an absorption peak in the infrared region,which had a wider light absorption range than TiO₂/BC.（3）Used La-TiO₂/BC to carry out the NOR adsorption-photocatalytic degradation experiment,the removal effect of NOR by the composite was better under acidic conditions.When the material dosage was 0.2g/L and the mass concentration was10mg/L,the removal rate of NOR by La-TiO₂/BC was 82.14%.Mass spectrometry analysis found that the degradation of NOR by La-TiO₂/BC was mainly through three pathways:defluorination,piperazine ring decomposition and decarboxylation.（4）Preparation of magnetically recyclable La-TiO₂/MBC.Due to the introduction of magnetic substances,the NOR removal effect of La-TiO₂/MBC with the same mass was weaker than that of La-TiO_2/BC,but the material had good magnetic separation and recovery performance.The two materials,La-TiO₂/BC and La-TiO₂/MBC,were recycled for three times,and the removal rate decreased by about 10%,so the material has the reusability...