Study On The Adsorptive Performance Of Typical Antibiotics From Aqueous Solution By Modified Biochars Derived From Potato Straw

Antibiotic are used worldwide for the treatment of diseases in human and animals,which can enter into the water environment and remain in the aquatic environment through incomplete metabolism of human and animals body.And the residual antibiotic had been frequently detected in the aquatic environment.The antibiotic contamination of water environment has become a new environmental issues that causing ecological and health risks.The study of new technology to remove antibiotic in water environment is significant in reducing the environmental risks caused by antibiotic.Biochar as an economical and environmentally friendly novel adsorbent can adsorb antibiotic pollutant effectively.In order to further enhance the adsorption capacity of biochar and optimize its surface structure and physicochemical properties,several kinds of modefied biochars with good adsorption properties to tipical antibiotics were prepared in this paper.And they were used as adsorbents to study the adsorption characteristics of sulfonamides and fluoroquinolones antibiotics in aqueous.It provides a theoretical basis for the practical application of biochar for the removal of antibiotic contaminants.The main research contents and research results are as follows:Biochar（BC）was prepared by using potato straw as raw biochar,which was modified with H₂SO₄ and KOH to prepare acid/alkal modified biochar（HBC,KBC）.The characterization analysis of the three kinds of biochar which before and after modification showed that the BET specific surface area and pore volume of HBC and KBC decreased,and the surface oxygen-containing functional groups increased.Batch equilibrium experiments showed that the adsorption kinetics was fitted well with the pseudo-second order model.Temkin model could describe adsorption isotherm of ST onto HBC better,but those of BC and KBC were fitted well with Freundlich model.The adsorption of ST onto HBC was a spontaneous endothermic process,while that of BC and KBC was exothermic process.The mechanisms of adsorption for ST onto three biochars were attributed to a combination of hydrogen bonding,van der waals forces and dipole forces.MnO_x-magnetic biochar（MMB）was prepared by KMnO₄ and FeCl₃·6H₂O modifying biochar.The characterization analysis of the MMB showed that the BET specific surface area increased,pore volume decreased and the surface oxygen-containing functional groups increased.Batch equilibrium experiments showed that the adsorption kinetics of ENR,CIP and NOR onto BC and MMB were fitted well with the pseudo-second order model.Langmuir model could describe adsorption isotherm better.All adsorption processes were spontaneous endothermic.The adsorption of the three antibiotics on MMB was easier in acidic conditions.After 3 reuses of MMB,the removal rate was still greater than 95%.The mechanisms of three antibiotics onto the BC and MMB may be attributed to a combination ofπ-πEDA interactions,cation exchange,hydrogen bond and electrostatic attractions.HA-magnetic biochar（HAB）was prepared by humic acid and FeCl₃·6H₂O modifying biochar.The characterization analysis of the HAB showed that the BET specific surface area and pore volume decreased,the surface oxygen-containing functional groups increased.Batch equilibrium experiments showed that the adsorption kinetics of ENR,CIP and NOR onto HAB were fitted well with the pseudo-second order model.Langmuir model could describe adsorption isotherm better.All adsorption processes were spontaneous endothermic.The adsorption of the three antibiotics on HAB was easier in alkalic conditions.The mechanisms of three antibiotics onto the HAB may be attributed to a combination ofπ-πEDA interactions,hydrogen bond and electrostatic attractions.