Adsorption And Degradation Of Tebuconazole By Nanoscale Zero-Valent Iron Modified Biochar

Tebuconazole is a kind of high efficiency and wide spectrum of inhaled triazole fungicides,which is widely used in agricultural production all over the world.However,excessive use and abuse have led to frequent detection or excessive residues of tebuconazole in some agricultural products and environmental media,and the problem of ecological environmental pollution has gradually become prominent.Therefore,how to effectively remove the tebuconazole in environmental media such as water and soil is an urgent problem to be solved.In recent years,biochar（BC）has attracted great attention in the field of environmental pollution remediation due to its wide range of sources,low cost,good adsorption performance and environmental friendliness.As a supporting material,biochar is modified by doping other materials or other metal elements to improve its physical and chemical properties and apply it to environmental remediation,which has also attracted extensive attention from scholars.Based on this,for the removal of tebuconazole in environmental media,this experiment prepared nanoscale zero-valent iron modified biochar（BC-n ZVI）,and used a variety of characterization methods.The surface morphology and functional groups of the materials were analyzed,and the adsorption and degradation performance of the modified biochar and biochar on tebuconazole was compared.The mechanism and removal performance of the modified biochar were discussed,and the biological safety of the modified biochar was evaluated,so as to provide a new material and method basis for the remediation of environmental pollution caused by common fungicides.The results of the study are as follows:（1）BC-n ZVI were prepared and characterized.Nanoscale zero-valent iron（n ZVI）and BC-n ZVI（carbon to iron ratio 3:1 and 5:1）were successfully prepared by liquid phase reduction method.The materials were characterized by scanning electron microscopy（SEM）,transmission electron microscopy（TEM）,X-ray diffraction（XRD）,Fourier transform infrared spectroscopy（FTIR）and X-ray Photoelectron Spectroscopy（XPS）.SEM image showed nanoscale zero-valent iron is uniformly and dispersed inside the porous structure of biochar and on the surface of biochar.TEM spectra showed that nanoscale zero-valent iron is nanometer.The（110）surface of n ZVI was observed by high resolution transmission electron microscopy and selected electron diffraction spectra,which proved that there were nanoscale zero-valent iron on the surface of biochar.FTIR spectrum showed that iron is successfully loaded on the biochar,and the functional group types and strength of BC-n ZVI change greatly.XRD spectrum shows that Fe in BC-n ZVI is zero-valent state.XPS spectra showed that the main element on the surface of modified biochar was Fe,C,O,and there were abundant functional groups on the surface.（2）Study on the adsorption and degradation characteristics of BC-n ZVI for tebuconazole in aqueous solution.The results showed that compared with BC,BC-n ZVI could enhance the adsorption and degradation of tebuconazole in aqueous solution,and the BC-n ZVI with a carbon-iron ratio of 3:1 had the best adsorption and degradation effect.When0.2 g·L^-1was added,the adsorption rate and degradation rate of BC-n ZVI with the ratio of carbon to iron 3:1 reached 36.48%and 23.36%,respectively,which were 8.81%and13.38%higher than that of BC,respectively.The isothermal adsorption experiments showed that the adsorption capacity of BC-n ZVI for tebuconazole was higher than that of BC.（3）The removal effect of BC-n ZVI on the tebuconazole in soil-water suspension was discussed.The soil-water suspension experiment showed that the adsorption and degradation amount of the tebuconazole in the BC-n ZVI treatment group was significantly higher than that in the control group and the BC treatment group,indicating that BC-n ZVI had a good effect on the removal of the residue of the tebuconazole in the soil,which further verified the feasibility of the application of BC-n ZVI.（4）Verification of the effect of BC-n ZVI on the removal of tebuconazole and its safety evaluation under hydroponic conditions.Through hydroponic experiments,it was found that BC and BC-n ZVI could improve the germination rate of seeds,reduce the residual amount of tebuconazole in hydroponic solutions and plants,and had a better removal effect on the removal of tebuconazole under hydroponic conditions.In addition,0.2 g·L^-1BC and BC-n ZVI could promote the growth of cucumber seedlings to a certain extent,which provided data for the biosafety evaluation of cucumber seedlings.