Investigation On Removal Of Antibiotics And Dyes Onto Fe/Cu Nanocomposites From Aqueous Solution

The treatment of antibiotics and dye wastewater has recived particular attention since antibiotics extensive use and the discharge of dye wastewater have seriously threatened human health.Metal nanomaterials as adsorbents for the treatment of wastewater pollutants have been hotspots in recent years due to their high mechanical strength,small particle size,large specific surface area and large surface energy.Compared with traditional chemical and physical preparation methods,the method of plant green synthetic metal nanoparticles has the advantages of low cost,simple operation,no harmful substances,fast reaction speed and no secondary pollution.Iron,copper nanocomposites（Fe/Cu NCs）were produced by Pine needle extract and were adopted as a potential adsorbent for the removal of two fluoroquinolone antibiotics（norfloxacin（NOR）and ofloxacin（OFLX））and an anionic dye（Acid chrome blue K（ACBK））from aqueous solution.The adsorption behavior and mechanism were analyzed.The optimum preparation conditions of Fe/Cu NCs by single factor experiment were obtained using Pine needle extract（solid-liquid ratio）of 140 g/L,extraction solution volume of 150 m L,0.085 mmol/L metal salt solution of 20 m L and reaction time of 5 h.To understand the morphologies and properties of Fe/Cu NCs,surface analysis via SEM,EDS,TEM,XPS,FTIR,BET and p H_PZCpattern were employed.The results showed that Fe/Cu NCs were quasi-spherical and had a specific surface area of 27.8 m²/g.There were reactive functional groups such as hydroxyl and carboxyl groups on the surface of Fe/Cu NCs.And the p H_PZCof Fe/Cu NCs was 4.02.The effects of factors such as adsorption time,initial p H,adsorbent dose,ionic strength,reaction temperature and initial concentration on the adsorption capacity of NOR,OFLX and ACBK on Fe/Cu NCs were studied.Moreover,the kinetic model and isotherm model were used to analyze the adsorption process.It was observed that the adsorption equilibrium time of Fe/Cu NCs for NOR and OFLX was 180 min and the optimal adsorption p H was 8.12 and 8.87,respectively.The adsorption amount was positively related to the solution temperature and initial concentration.However,the addition of salt ions was not conducive to the adsorption process.The adsorption kinetics data of NOR and OFLX on Fe/Cu NCs were well fitted by Double-constant rate equation and Elovich equation,and the adsorption isotherms data were well described by Redlich-Peterson,Koble-Corrigan and Dubinin-Radushkevich models.The maximum adsorption capacity of Fe/Cu NCs calculated by Langmuir model for NOR and OFLX was 1.64 mmol/g and 1.26 mmol/g at 293 K,respectively.Thermodynamic results（ΔG,ΔH,ΔS）indicated that the NOR or OFLX adsorption on Fe/Cu NCs was spontaneous and endothermic and it performed better at higher temperature.The adsorption conditions of Fe/Cu NCs for ACBK were obtained using adsorption equilibrium time of 240 min and natural p H value of ACBK.It was also clear that the adsorption uptake increased as ionic strength increased.The process of adsorption ACBK on Fe/Cu NCs could be described by Elovich and pseudo-second-order equation.And the adsorption process followed Koble-Corrigan,Dubinin-Radushkevich and Langmuir isotherm models.The maximum monolayer adsorption uptake of Fe/Cu NCs calculated by Langmuir model for ACBK was 0.510mmol/g at 293 K.In addition,the negative value of?G and?H indicated the adsorption of ACBK on Fe/Cu NCs was spontaneous and exothermic.Combine the results of the infrared analysis and the effects of p H values on the adsorption capacity,the adsorption mechanism of NOR and OFLX on Fe/Cu NCs were involved a combination of electrostatic interaction,the formation of hydrogen bonds,π-πstacking interactions,surface complexation,hydrophobic interaction;the adsorption mechanism for ACBK were electrostatic interaction,π-πstacking interactions and hydrogen bonding.