Effect Of Modification Of Activated Carbon On Its Adsorption Of Bilirubin

Objective:1.To investigate the effect of modification of activated carbon using nitric acid（HNO₃）,hydrogen peroxide（H₂O₂）and potassium permanganate（KMnO₄）as reagents on its free bilirubin and bound bilirubin adsorption.2.To investigate the role of the texture and surface oxygenic groups of activated carbon on the adsorption of free bilirubin and albumin-bound bilirubin.Methods:Activated carbon was modified by HNO₃,H₂O₂ and KMnO₄ for different time,then was characterized by Boehm titration,static liquid nitrogen adsorption instrument and scanning electron microscope.The adsorption kinetics and isothermal adsorption of bilirubin on activated carbon were measured to investigate the effect of modification on the adsorption of free bilirubin and albumin-bound bilirubin.The effects of vibrating speed,pH on its adsorption were also investigated.Results:1.The oxygen-containing functional groups on the surface of activated carbon modified by HNO₃ and H₂O₂ were greatly increased.The number of acidic functional groups of the activated carbon modified by HNO₃ was higher than that of the activated carbon modified by H₂O₂,and C-H-6（activated carbon modified by HNO₃ for 6 h）with the highest acid group content is 3 times as much as C-0（unmodified）.BET results show that all the three modification methods can oxidize and dissolve the activated carbon make mesopores increase.SEM results showed that the activated carbon modified by different reagents had different morphological characteristics.Activated carbon modified by HNO₃ and H₂O₂ has many channels,in a state of close arrangement.The activated carbon modified by KMnO₄ has enlarged pores and attached a lot of flaky crystalline materials.Proper modification time can make the modified activated carbon have excellent adsorption properties.The modification time is too long,which is not conducive to the modification of activated carbon.2.The adsorption performance of HNO₃ modified activated carbon on free bilirubin andalbumin-bound bilirubin has been improved.The adsorption of free bilirubin was mainly related to mesopores and acidic groups,while the adsorption of albumin-bound bilirubin was mainly related to acidic groups.C-H-6 with the highest content of acidic groups was 3times higher than that of C-0 before modification.Activated carbon modified by H₂O₂increased the adsorption capacity of free bilirubin.The adsorption capacity of bilirubin on activated carbon modified by KMnO₄ was also improved.3.Vibrating speed will obviously affect the adsorption of bilirubin by modified activated carbon,and the adsorption of bilirubin by modified activated carbon is greatly affected by pH of solution.Conclusion:Activated carbon modified by HNO₃,H₂O₂ and KMnO₄ can increase the specific surface area and pore volume of activated carbon,and the acidic groups on the surface of activated carbon increased significantly after oxidation by HNO₃ and H₂O₂.Bilirubin adsorption is closely related to the surface texture and groups of activated carbon.Modification is an effective method to improve the adsorption of bilirubin on activated carbon.Vibrating speed and pH will significantly affect the adsorption of bilirubin on modified activated carbon.