Preparation Of Sargassum Horneri Based Activated Carbon Coated With Iron Oxide By In-situ Method For The Removal Of Methylene Blue

Activated carbon is a kind of adsorbent and catalyst support with high specific surface area and stable chemical properties,which has been widely used in the treatment of wastewater.The pore structure and surface chemical properties of activated carbon vary greatly depending on the raw material and preparation method,resulting in a large difference on the adsorption performance for different adsorbates.Studies have shown that a certain amount of iron and iron oxides could be coated on activated carbon by modification,which would improve its adsorption and catalytic ability.Sargassum Horneri based activated carbon coated with iron oxide?Fe/SAC?was prepared by ultrasonic immersing and in-situ synthesis method using Sargassum Horneri as raw material and Ferric chloride hexahydrate as activating agent.Effects of activation temperature,activation time and impregnation ratio on the Fe/SAC yield and methylene blue?MB?value were investigated by orthogonal experiments.The optimized Fe/SAC was characterized with X-ray diffraction,Scanning Electron Microscopy and Surface Area Analyzer.Furthermore,the kinetics,equilibrium and thermodynamics of MB adsorption onto Fe/SAC were studied.The composite was used as adsorbent and catalyst for heterogeneous Fenton reaction separately,and methylene blue was selected as the target pollutant.The effects of different conditions on the removal of methylene blue were studied.Meanwhile,the regeneration performance of Fe/SAC was investigated.The results indicated that:?1?The Fe/SAC yield,MB value,specific surface area and average diameter could reach 39.5%,255.67 mg·g^-1,558.31 m2·g^-1 and 7.7 nm under the optimal parameters with activation temperature of 600 ?,activation time of 1 h and impregnation ratio of 1:1.The adsorption value of methylene blue increased about 42% compared with that of ZnCl₂ activation.Fe₃O₄ and FeO were the main components coated on Fe/SAC.?2?The adsorption of MB onto Fe/SAC was found a chemical adsorption process,which could be described by pseudo-second-order equation well.?3?The Langmuir model provided the best correlation of the equilibrium data and saturated adsorption capacity of MB reached 268.10 mg·g^-1 at 313 K.Calculation of ?G,?H and ?S indicated that the adsorption of MB onto Fe/SAC was an entropy increasing,spontaneous and endothermic process,which was promoted by increasing process temperature.?4?As a new catalyst for heterogeneous Fenton reaction,Fe/SAC has high catalytic activity,which would exhibit a good performance on the treatment of MB wastewater compared with adsorption.Heterogeneous Fenton reaction was affected by the factors of initial concentration of solution,pH value,reaction temperature,Fe/SAC dosage and H₂O₂ dosage.?5?Fe/SAC has high stability,low iron ion leaching and excellent regeneration performance in heterogeneous Fenton reaction.