Study On The Removal Mechanism Of Tylosin By The Modification Of Waste Biomass

Renewable agricultural waste biomass are produced in huge quantities,and their storage and management create environmental problems.Similarly,antibiotics could cause harm to the ecosystem and the growth of plants and animals.As one of the widely used antibiotics in the world,the environmental risks of tylosin(TYL)received more and more attention.In order to find clean and effective method for TYL remove from aqueous solution,maize straw was used as a sorbent,and modified by goethite,iron oxides,mangmnese oxides and sulfide.The sorption capacity of natural and modified forms were investigated for TYL removal.The main experiments and conclusions are as follows:1.Goethite modified maize straw to remove TYL from aqueous solutions.The results indicate that the sorption ability of TYL on MSF(maize straw modified by goethite)significantly higher than MS(original maize straw);the sorption kinetics data of TYL on MS and MSF well fits the pseudo-second-order kinetics model and the sorption isotherms data well fits Henry model.Besides,the sorption of tylosin on MS and MSF can be affected by p H and ionic strength of solution.The sorption mechanisms of tylosin on MS mainly involed electrostatic interactions,H bonding and hydrophobic interactions,while electrostatic interactions,H bonding,hydrophobic interactions and surface complexation might play a primal role in the sorption of TYL on MSF.2.Iron and manganese oxides modified maize straw to remove tylosin from aqueous solutions.The results showed that maize straw was successfully modified and maize straw modified by iron and manganese oxides has a larger surface area than MS.According to the experimental data,the sorption ability of tylosin on sorbents followed the order of MS < MS-M(maize straw modified by manganese oxides)< MS-FM(maize straw modified by iron and manganese oxides).The study indicated that manganese oxides and iron-manganese oxides could significantly enhance the sorption capacity of original maize straw.The sorption isotherm data of tylosin on MS-M and MS-FM well fit Freundlich models.It is complex to explain the removal mechanisms of tylosin considering the surface complexes,electrostatic interactions,H bonding and hydrophobic interactions.In addition,the p H,temperature and ionic strength also affect the sorption process.3.Maize straw decorated with sulfide for tylosin removal from the water.The results of fitting the experimental data showed that the sorption conforms to the pseudo-second-order kinetics,and the TYL sorption on MS fit the Henry model well,but the Freundlich model was more suited to MS-Zn S and MS-Zn S:Mn.In addition,the kf values of MS-Zn S(206.0(mg/kg)/(mg/L)n)and MS-Zn S:Mn(382.5(mg/kg)/(mg/L)n)were significantly greater than that of MS(72.2(mg/kg)/(mg/L)n),indicating that Zn S and Zn S:Mn could improve the sorption capacity of TYL on MS.The sorption ability of TYL on MS-Zn S and MS-Zn S:Mn showed little change when the solution p H was > 5;the amount of TYL sorption on the adsorbents gradually decreased with the increasing concentration of KNO3.Compared with MS,the main mechanism is surface complexation in the sorption of TYL on MS-Zn S and MS-Zn S:Mn.