Study On The Adsorption Characteristics Of Quinolone Antibiotics Onto Fe-Cu Nanocomposites

Antibiotics are widely used in the treatment of human,livestock and poultry diseases.A large amount of antibiotic wastewater is produced in the production and use processes,which poses a serious threat to human health and ecological balance.Adsorption is one of the effective methods to treat antibiotic wastewater.As agricultural waste,peanut vines contains polyphenols and flavonoids which can be used as reducing agents to synthesize metal nanomaterials.In this paper,the Fe-Cu nanocomposites(ICNCs)were synthesized by the peanut vine extracts,and the adsorption properties of quinolone antibiotics pefloxacin(PFX),enrofloxacin(ENR)and lomefloxacin(LMX)on ICNCs were investigated,to lay a foundation for the treatment of quinolone antibiotic wastewater by adsorption.Firstly,ICNCs were prepared by the peanut vine extracts.Fe-Cu nanocomposites was characterized by XPS,SEM,FTIR,BET,XRD and EDS.The adsorption characteristics of PFX,ENR and LMX onto ICNCs were investigated.The effects of adsorption time,dosage of ICNCs,solution p H,temperature and initial concentration of antibiotics on the PFX,ENR and LMX adsorption processes were studied.The results showed that the adsorption equilibrium time of ICNCs for PFX,ENR and LMX was 360 min,and the optimal dosage of ICNCs was 0.5 g/L.Five adsorption isotherm models were employed to evaluate the adsorption behavior of PFX,ENR and LMX on ICNCs.The results revealed that the equilibrium adsorption data of PFX on ICNCs were well described by the Langmuir,Koble-Corrigan and Sips isotherm models.The adsorption behavior of ENR and LMX on ICNCs were well describe by the Langmuir,Sips,Redlich-Peterson and KobleCorrigan models.At 298 K,the maximum monolayer adsorption capacity of ICNCs for PFX,ENR and LMX were 240.70 mg/g,222.03 mg/g and 172.47 mg/g,respectively.Thermodynamic parameters showed that the adsorption process of PFX,ENR and LMX onto ICNCs were entropy increasing,spontaneous and endothermic in nature,indicating that the adsorption process of PFX,ENR and LMX on ICNCs become more favorable at higher temperature.Kinetic studies revealed that the adsorption data of PFX,ENR and LMX on ICNCs followed the pseudo-second-order model well,and the adsorption rate was affected not only by the intra-particle diffusion,but also by the boundary layer diffusion.The adsorption mechanisms of PFX,ENR and LMX on ICNCs were discussed.The adsorption of PFX,ENR and LMX on ICNCs could be affected by the hydrogen bond,π-π and n-π adsorbate-adsorbent interaction,hydrophobic effect,complexation and electrostatic interaction between ICNCs surface functional group and the molecular species variations of adsorbate.The results showed that ICNCs had good adsorption capacity for PFX,ENR and LMX,and could be used as an ideal adsorbent for the treatment of quinolone antibiotic wastewater.