| The discharge of industrial wastewater without effective treatment and exceeding the standard has brought severe challenges to the water environment safety in China.At the same time,the burning of agricultural wastes also caused serious air pollution.pollution.In order to weaken the negative effects of lead and BPA in industrial wastewater on the ecological environment and realize the resource utilization of agricultural waste,this paper prepared a new adsorbent named RH@β-Fe which could be quickly separated from water to effectively remove lead ions and BPA from water.RH@β-Fe was prepared from rice husk with proper modification,which is a kind of cheap and easily available agricultural.The results of this study about rice husk was used as the substrate to prepare a kind of adsorption material and this adsorption material could effectively remove lead and BPA in water can provide reference for the way of resource utilization of agricultural waste and theoretical guidance and technical support for the treatment of industrial lead smelting wastewater and resin wastewater.RH@β-Fe was synthesized by grafting β-cyclodextrin with epichlorohydrin as a crosslinking agent,and then by cross-linking iron tetroxide with chloroacetic acid.The adsorption capacity of RH@β-Fe for Pb（Ⅱ）in water was as high as222.85mg/g,and the adsorption capacity for BPA in water was as high as 155.17mg/g.The optimal preparation conditions of RH@β-Fe were determined by single factor experiments and orthogonal optimization experiments as follows: the dosage of β-cyclodextrin was 0.2g/ 0.2g of carbonized rice husk,the preparation time of modifier was 60min,and the modification time was 7h.Some characterization methods including FTIR,SEM,EDS,XRD were used to confirm the successful preparation of RH@β-Fe.RH@β-Fe is a kind of soft magnetic material with strong magnetic properties and can be separated from water effectively,which was confirmed by VSM and sedimentation comparison experiments.RH@β-Fe showed higher adsorption capacity for Pb（Ⅱ）at neutral p H and near-neutral acidic conditions,and its adsorption time was only 20～30min.The adsorption capacity of Pb（Ⅱ）by RH@β-Fe was increased by heating.The adsorption process mainly conformed to the pseudo-second-order kinetic model and Langmuir model.At 25°C,the maximum adsorption capacity of Pb（Ⅱ）by RH@β-Fe was estimated to be 241.03mg/g according to the parameters of Langmuir model.The adsorption thermodynamic analysis showed that the adsorption process was a spontaneous endothermic process and the molecular disorder increased.Correlation experiments and XPS analysis results showed that the adsorption of Pb（Ⅱ）by RH@β-Fe was mainly dependent on ion exchange and complexation of oxygen-containing functional groups on the surface.When RH@β-Fe was applied to the treatment of simulated wastewater from a lead smelting plant,the discharge of lead ions could be achieved up to standard,which shows a high practicability.RH@β-Fe had high p H adaptability and short adsorption saturation time about 10min when it was used to adsorb BPA.The pseudo-second-order kinetic model and Langmuir model were more suitable to describe the adsorption process of RH@β-Fe for BPA.The adsorption process of RH@β-Fe to BPA was also a spontaneous endothermic process.And the molecular disorder increased after adsorption.At 25°C,the maximum adsorption capacity of BPA by RH@β-Fe was estimated to be 341.42mg/g according to the parameters of Langmuir model.The adsorption sites of BPA and Pb（Ⅱ）on RH@β-Fe surface were different.RH@β-Fe showed preferential adsorption for BPA when was used to adsorb BPA/Pb（Ⅱ）composite system.Its adsorption capacity of BPA is not affected,and its adsorption capacity of Pb（Ⅱ）is slightly decreased.Thus,the research of this paper also provides basic data and technical support for the collaborative removal of BPA and Pb（Ⅱ）mixed wastewater. |
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