Study on characteristics of wheat straw loaded with nano-hydrated iron oxide for removing Cu2+from water
In this study,nanocomposite materials were developed combining straw resource utilization with wastewater treatment.The two-dimensional sheet nanocomposite adsorbent WS-HFO was prepared by stable loading of hydrated iron oxide(HFO)nanoparticles on the surface of wheat straw through a mild and simple impregnation method for the removal of heavy metal Cu2+in water.The adsorption performance and mechanism of WS-HFO for Cu2+were also explored.SEM characterization revealed significant changes in the microstructure of wheat straw,and the diameter of loaded HFO nanoparticles was 50-80 nm.Specific surface area and pore size distribution of the materials were determined by N2 adsorption/desorption curves.In the dosing experiments,removal rate of 50 mL 16 mg/L Cu2 by 0.07 g WS-HFO was almost 100％.Solution pH had a great influence on the Cu2+adsorption onto WS-HFO,and the adsorption capacity was maximum at pH 5.9.Competitive adsorption experiments proved that high concentrations of coexisting cations Na+,Mg2+and Ca2+were not conducive to the adsorption of low concentration Cu2+.The adsorption kinetics of WS-HFO for Cu2+followed pseudo-second dynamics equation,the adsorption isotherm conformed to Langmuir model.WS-HFO had strong adsorption affinity for Cu2+.The fixed-bed column adsorption/desorption running showed that 1.8 g WS-HFO could effectively treat 1 980 mL simulated wastewater with the average effluent Cu2+concentration below 0.05 mg/L.When 4 mol/L NaCl was used as desorption agent,the removal rate of Cu2+could remain at 89％-100％in the 7 recycling tests.
wheat strawhydrated iron oxidenanocompositesadsorptionheavy metal
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