Performance And Mechanism Of BPA Adsorption Onto Magnetically Ordered Mesoporous Carbon

With the continuous development of human industry,the number and type of environmental endocrine disruptors are increasing,which has become the focus of global attention.This study focused on the pollution problem of bisphenol A（BPA）,a typical endocrine disruptor,the adsorption performances and mechanism of different carbon-based materials and ordered mesoporous carbon loaded with Fe3O4 were investigated,and the feasibility of practical application of this new carbon-based material was evaluated.Firstly,the adsorption capacities of activated carbon（AC）,single-walled carbon nanotubes（SWCNTs）,multi-walled carbon nanotubes（MWCNTs）,ordered mesoporous carbon（OMC）and graphene oxide（GO）on BPA were systematically compared.Through the characterization,OMC possesses the largest specific surface area and pore volume,and the surface of five carbon-based materials all contain oxygen-containing functional groups such as hydroxyl and carboxyl groups.The order of adsorption capacity of different carbon-based materials followed the order of OMC>AC>SWCNTs>GO>MWCNTs.Adsorption kinetic study indicated that the BPA adsorption on different carbon-based materials could be described by pseudo-second-order kinetic model.Langmuir adsorption isotherm model can better fit the BPA adsorption on all carbon-based materials,and the adsorption process was spontaneous and exothermic.When the solution pH was close to the value of pH_pzc,the carbon-based materials all showed the best adsorption performance,and the adsorption capacity decreased below or above the value of pH_pzc.The poorest adsorption performance was observed at pH 11.Magnetically ordered mesoporous carbon was successfully synthesized through hydrothermal method.Through the characterization,Fe₃O₄ nanoparticles were successfully loaded on the surface of OMC.The as-prepared magnetically ordered mesoporous carbon still possessed the abundant mesoporous structure,whith a specific surface area of 420.14 m2/g,a pore volume of 0.493 cm³/g and a saturation magnetization of 12.5 emu/g.The BPA adsorption by magnetically ordered mesoporous carbon mainly occurred in the first 200 min,and then reached the adsorption saturation by 400 min.With the increase of loading amount of Fe₃O₄nanoparticles,the adsorption capacity of magnetically ordered mesoporous carbon gradually decreased.The best adsorption performance can be obtained near the value of pH_pzc(pH_pzc=7.8).The BPA adsorption by magnetically ordered mesoporous carbon followed the pesudo-second-order kinetic model,and Langmuir adsorption isotherm model can better decsribe the BPA adsorption process.The thermodynamic study showed that the adsorption process is spontaneous and exothermic.The magnetically ordered mesoporous carbon possessed good stability and reusability,and had favorable adsorption capacity on different emerging organic pollutants,which indicated that the new carbon-based material possessed good application prospect in the field of water treatment.