Adsorption Behavior Of Pb²⁺ And Phenol By Activated Carbon Prepared By Shaddock Peel

Four kinds of shaddock peel-based activated carbon were prepared using shaddock peel as raw material and Zn Cl₂and H₃PO₄as activation agents,under different preparation conditions?changing activation temperature and activation time?,and a series of characterization including SEM-EDS,N₂adsorption,FTIR analysis,TG-DTG analysis,XPS analysis and Boehm titration were used to study the physical and chemical properties of shaddock-peel-based activated carbon surface.The effects of single factors on adsorption of Pb²⁺and phenol were explored by changing different adsorption conditions?initial solution concentration and adsorption time?,and experimental data were fitted with pseudo-first-order,pseudo-second-order and the Elovich kinetic model,respectively.Furthermore,the competitive adsorption experiments of Pb²⁺and phenol,Pb²⁺and Cu²⁺were explored by controlling ionic strength and p H,and compared with single component adsorption respectively,then the competitive adsorption data were also fitted by the Langmuir,the Temkin and the Freundlich isotherm.Z-800-30 and H-800-90 were modified by adding oxygen-containing functional groups on the surface,removing oxygen-containing functional groups on the surface and removing only carboxyl groups,respectively,to explore the main types of surface functional groups affecting adsorption.N₂adsorption,Boehm titration and FTIR characterization and comparison of the samples before and after modification were made to investigate surface chemical properties of the modified samples.Based on the above studies,the following conclusions have been drawn:?1?Through EDS and XPS analysis,the main components and contents of shaddock-based activated carbon were obtained,and activated carbon prepared by H₃PO₄has higher oxygen content.From the results of N₂adsorption analysis,it can be concluded that the type of activator has the greatest influence on the pore structure of activated carbon,while activation time has little effect.FT-IR analysis and Boehm titration indicate that the activated carbon phosphate contains more oxygen-containing functional groups on the surface,and thermogravimetric analysis proved that four kinds of activated carbon are of strong thermal stability.?2?The equilibrium time of adsorption Pb²⁺of four kinds of shaddock-peel-based activated carbon is about 600 min,and the equilibrium time of adsorption of phenol is about 300 min.Pb²⁺adsorption capacity of activated carbon was much higher than that of activated carbon prepared by Zn Cl₂,while the adsorption of phenol by activated carbon prepared by Zn Cl₂was better.At lower concentration range,the removal rate of Pb²⁺and phenol increased with the increase of initial concentration,and at higher concentration,the removal rate decreased with the increase of initial concentration.?3?Elovich model is more suitable to describe the adsorption Pb²⁺of four shaddock peel-based activated carbon and the adsorption of phenol on activated carbon prepared by Zn Cl₂,whereas the pseudo-second-order model better meets with the adsorption of activated carbon prepared by H₃PO₄for phenol.?4?The presence of phenol has little effect on the adsorption of Pb²⁺,but it will inhibit the adsorption of phenol when Pb²⁺coexist;there is a strong competitive relationship between Cu²⁺and Pb²⁺,and the two ions inhibit adsorption each other.?5?It is proved that carboxyl group is the main functional group in oxygen-containing functional groups,which will inhibit the adsorption of phenol and decrease the adsorption of heavy metal ions after surface modification onto shaddock-peel actived carbon.