Research On Treating Low-Concentration Chromium Wastewater By Adsorption

Chromium-containing wastewater was often treated by chemical precipitation.The Cr?VI?in effluent was not stable for the fluctuation of water quality.In this study,some high efficient adsorbents were developed to treat low concentration chromium wastewater in order to achieve the stable and up-to-standard discharge of Cr?VI?.The experimental results were as follows:1)CeO₂@ZSM-5 was prepared by impregnation method.When the initial concentration of Cr?VI?was 2mg·L^-1,the optimum adsorption conditions were pH 3,dosage 3g·L^-1 and reaction time 70min.The removal rate of Cr?VI?reached 90.56%.The saturated adsorption capacity was 0.239mg·g^-1.The adsorption process accords with Freundlich isothermal adsorption model and pseudo-second order kinetic model.2)Iron-modified ceramsite?FMCA?was prepared by impregnation method.When the initial concentration of Cr?VI?was 2mg·L^-1,the optimum adsorption conditions were pH 4,dosage 1g·L^-1 and reaction time 120min.The removal rate of Cr?VI?reached93.21%.The saturated adsorption capacity was 3.572mg·g^-1.The adsorption process accords with Freundlich isothermal adsorption model and pseudo-second order kinetic model.3)Oxytetracycline residue activated carbon?Bacterial slag charcoal?was prepared by activation method.When the initial concentration of Cr?VI?was 2mg·L^-1,the optimum adsorption conditions were pH 4,dosage 0.5g·L^-1 and reaction time 50min.The removal rate of Cr?VI?reached 96.20%.The saturated adsorption capacity was 17.930mg·g^-1.The adsorption process accords with Freundlich isothermal adsorption model and pseudo-second order kinetic model.