Experimental Study Of New Nano Iron Content To Remove Cr(?) In Wastewater

Iron based materals including iron hydroxides and iron sulfide were used successfully for remediation of environment which polluted by heavy metal.Geothite were always considered to be important environmental materal which could be functioned as adsorbent for heavy metal.Due to large specific surface area and more active sites,the use of pyrite as reactive media for treatment of heavy metal.Influencing factors,adsorption isotherm and adsorption kinetics of the absorption of chromium on goethite(?-FeOOH)were studied using simulated wastewater.The effects of initial Cr(?)concentration,pH,the amount of absorbent,ionic strength on removal of Cr(?)by goethite were investigated.Experimental results indicate that adsorption equilibrium of goethite was achieved within 30 min and at pH=3,favors goethite adsorption of Cr(?)efficiency is the highest.The concentration of Cr(?)at 15 mg/L the best goethite dosing quantity was 2 g/L.Adsorption of Cr(?)reduced with the increase of ionic strength.Adsorption of Cr(?)increase with temperature.Adsorption of Cr(?)on goethite at 35? could be described more exactly by Freundlich equation(R2=0.9952)than by Langmuir equation and Temkin equation.The adsorption process followed the pseudo-second-order equation.The activation energy(Ea)for the absorption reaction was 31.306 kJ/mol.Results of the study suggested that goethite has the potential ability for chromium removal from wastewater.Three different modified methods were studied.Phosphoric acid,humic acid and aluminium were used to modify goethite.The results suggested that the three different modified methods were poor,adsorption effect of ?-FeOOH modified by Al was decline from 64% to 54%.Adsorption effect of ?-FeOOH modified by phosphoric acid without obviously improved,and the equilibrium time was extended to 4h.Adsorption effect of ?-FeOOH modified by humic acid had some improve,but the adsorption equilibrium time was too long.Cr(?)removed by FeS was studied.Several operation parameters including temperature,pH,addition of FeS,and condition of Cr(?)was investigated.The results showed that adsorption equilibrium time of reaction was 30 min.Removal effient was increased by tempurture.At the initial pH was 2,Cr(?)was almost removed by FeS.The best addition of FeS was 0.2 g/L at concentration of Cr(?)was 40 mg/L.Reaction kinetic was studied at different conditions and followed the first order kinetics equation.The activation energy(Ea)was 31.306 kJ/mol,and the reaction was chemical reaction.