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采用液相还原法制备载铁活性炭,对负载铁前后及吸附铀离子U(VI)后的活性炭进行表征,考察了其吸附性能.结果表明,铁以球形疏散负载于活性炭的孔隙中,载铁后比表面积为10.3 m~2/g,孔容为0.0245 cm~3/g,最可几孔径为10.5 nm.吸附U(VI)过程中铁表面发生腐蚀并形成新晶体,比表面积增至16.7 m~2/g,孔容增至0.0955 cm~3/g,最可几孔径增至17.9 nm.载铁活性炭对水溶液中铀离子的吸附机理为吸附、氧化还原和沉淀.在Fe SO4?7H2O与活性炭质量比1.25/1、载铁活性炭投加量0.6 mg/m L、反应时间60 min及pH值5.00的条件下,水溶液中U(VI)的去除率最佳,达99.9%,U(VI)初始浓度和反应温度的影响较小.载铁活性炭吸附U(VI)的过程符合Freundlich(R2=0.992)和Langmuir(R2=0.943)吸附等温模型,动力学过程符合准二级动力学模型(R2=0.999),扩散速率主要由液膜扩散控制.
The activated carbon was prepared by liquid reduction method, and the activated carbon before and after iron loading and uranium ion U (VI) adsorption was characterized and its adsorption performance was investigated. The results showed that iron was spherically dispersed in the pores of activated carbon, The specific surface area is 10.3 m 2 / g, the pore volume is 0.0245 cm -3 / g and the most probable pore size is 10.5 nm.The iron surface is corroded and new crystals are formed during the adsorption of U (VI), the specific surface area increases to 16.7 m ~ 2 / g, pore volume increased to 0.0955 cm ~ 3 / g, and the most probable hole diameter increased to 17.9 nm. The adsorption mechanism of iron-supported activated carbon on the uranium ions in aqueous solution was adsorption, redox and precipitation. The best removal rate of U (VI) in aqueous solution was 99.9% under the optimal conditions of 1.25 / 1, 0.6 mg / m L of iron-activated carbon, reaction time 60 min and pH value of 5.00. (R2 = 0.992) and Langmuir (R2 = 0.943) adsorption isotherm model, the kinetic process accorded with quasi-second-order kinetic model (R2 = 0.999). The diffusion rate is mainly controlled by liquid film diffusion.