Preparation Of Gd/Fe-C Compasite Materialand Its Mechanism Of Organic Mater Degradation In Landfill Leachate

This research adopts the ferric chloride hexahydrate,activated carbon powder,soluble starch,gadolinium oxide,such as material,using water and high temperature sintering polyure preparation of Gd/Fe-C composites,with garbage leachate as a target the pollutant,because of the single factor experiment and the orthogonal design experiment to optimize the Gd/Fe-C the best preparation conditions of composite materials and through SEM,XRD,FTIR and XPS of rare earth elements in Gd before and after the reinforcement of composite materials were characterized;At the same time explore the Gd/Fe-C composites processing optimum process conditions of landfill leachate,the molecular weight by ultraviolet-visible analysis,cutting ultrafiltration,three dimensional fluorescence spectrum analysis preliminary qualitative mixed system,the kinds of organic matter in proven the degradation of organic matter type,molecular weight,size and functional groups,provide a basis for index in environmental water treatment and the actual engineering and technology reference,evaluate the risk as a biological pretreatment.The experimental results show that:(1)Because of single factor experiment and the orthogonal design experiment,the best conditions for preparing Gd/fe-c composite were as follows:quality ratio of Fe/C then(including starch content 20%),teflon inside the reaction kettle heating temperature is 120?,the rare earth content is 7%,calcination temperature 900?,tube furnace roasting heating rate of 5?,min 1,roasting time is 1.0 h.The order of influencing factors is as follows:Fe/C mass ratio>roasting temperature>heating temperature>rare earth addition amount.(2)After the addition of rare-earth element Gd,long strip crystals appeared in the material,and the surface of the material was more meticulous and compact.At the same time,the generation of iron oxides was inhibited,the amount of zero-valent iron and activated carbon was significantly increased,and more active C-O bonds and C-H bonds appeared.Rare-earth element Gd mainly exists in the material in the form of Gd³⁺,which increases the porosity of the material and makes the material have more contact area with landfill leachate,thus improving the treatment efficiency of the material.Gd/Fe-C material has higher strength and hardness,reducing material loss caused by collision and cracking during the reaction process.(3)Add 100m L of landfill leachate to the conical bottle,the solution p H adjustment to 6,the temperature is 25?,Add Gd/Fe-C composites 6 g,under the condition of the oscillation rate of 80 rad/min uniform shock 90 min,the most ideal effect on the degradation of waste leachate,namely the removal rate of COD_Cr,TOC and UV₂₅₄are 70.54%,56.13%and 97.27%respectively,the chroma removal rate was 97.37%.After treatment,the aromaticity of landfill leachate decreased,and the risk of environmental hazard decreased.(4)The main components in the leachate of the aged garbage are fullyzoic acid with a molecular weight of<30 k Da,accounting for 76.79%of the total soluble organic matter,followed by humic acid with a molecular weight of>30k Da,accounting for 23.21%.After treatment,most of the fulminoic acid was degraded,the content of small molecules with molecular weight<3 k Da in DOM increased from 31.89%to 69.21%,and the degree of aromatic unsaturation and humification decreased.The biodegradability BOD₅/COD increased from 0.036 to 0.307,which was more easily absorbed and utilized by biology.