| Hexavalent Chromium[Cr(Ⅵ)]is a very harmful heavy metallic pollutant. Common water treatment of coagulation sedimentation and biochemical technique is hardly to remove Cr(Ⅵ)from water.The adsorption on activated carbon(AC)is one of effective means for Cr(Ⅵ)removal.However,the shortages of adsorption capacity, regeneration and mechanical strength of AC baffle the application.In this dissertation, a new generation of carbon adsorbent,activated carbon fiber(ACF)was studied for Cr(Ⅵ)removal form water.Firstly,the influence factors,such as adsorption time,temperature,pH value of the solution and dosage on the adsorption were studied.The adsorption isotherms were obeyed Langmuir model at the optimal pH value(2～3),It was found that Cr(Ⅵ) adsorption by ACF was a chemical adsorption process.Secondly,ACF was modified by HNO3,H2O2 and O3,respectively,in order to improve its adsorption capacity for Cr(Ⅵ).Boehm titration and FTIR were used to characterize surface properties.The nitrogen adsorption was used to estimate the specific surface area and pore structure.The results showed that the modification could effectively change the functional groups and pore structure of the ACF.As a result,the modification increased the surface area and oxygen-containing groups on the carbon surface,so that enhanced the adsorption capacity of the resultant ACF.It suggested that large surface area and the oxygen-containing groups of ACF favor Cr(Ⅵ)removal.Finally,the three modified ACFs were subjected to static and dynamic adsorption of Cr(Ⅵ).The influence of adsorption time,temperature,particle size and dosage on Cr(Ⅵ)removal was investigated.The adsorption isotherms were obeyed Langmuir model.The results showed that ACF modified by H2O2 had the best adsorption performance.
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