Preparation Of NiCo(Al)LDHs Modified Straw Carbon Materials And Detection Of Heavy Metal Ions In Water

In view of the expensive traditional heavy metal detection instruments and complex detection conditions,this paper selects biomass carbon materials with abundant functional groups,and modifies them by layered double hydroxides with large specific surface area and large interlayer spacing,and two modifications are prepared.Sexual material.It has been characterized and tested by electrochemical methods to detect Pb(?),Cd(?),Cu(?),Hg(?),and the results show that this kind of composite material has a concentration of nmol·L^-1.Heavy metal ions have a high detection effect.(1)Using the hydrothermal method,the biomass charcoal is impregnated and mixed with LDHs,and the modified biomass charcoal composite materials with different molar ratios are successfully prepared by adjusting the ratio of the metallic element nickel and cobalt.The XRD test showed that NiCo-LDHs@BC showed characteristic diffraction peaks,which proved the existence of the layered structure of LDHs;FT-IR showed that LDHs and biomass carbon were compounded by the change of functional groups to break hydrogen bonds and form new chemical bonds.SEM and TEM show that the modified composite material is nanostructured and grows on the surface of biomass carbon in a needle-like state.Among them,NiCo-LDHs with a molar ratio of nickel and cobalt of 2:1 grows most on the carbon wall and carbon pores;The electrochemical workstation was used to detect Pb(?),Cd(?),Cu(?),Hg(?),and the detection concentration limits were1.146×10^-10mol·L^-1,9.364×10^-11mol·L^-1.1.237×10^-10 mol·L^-1,1.369×10^-10 mol·L^-1,both of nmol·L^-1 level.(2)Synthesize NiAl-LDHs@BC modified materials with different molar ratios using the same preparation method as in(1).The characteristic diffraction peaks of NiAl-LDHs appear in the XRD spectrum;FT-IR analysis shows that LDHs and biomass carbon materials are combined through chemical bonds,not simply mixed together;SEM and TEM results can directly see the LDHs on the surface of the material Nanosheets,in which NiAl-LDHs with a molar ratio of 2:1 grows most on the carbon wall and carbon pores;BET test shows that its specific surface area is 154.53 m²g^-1;XPS analysis shows that its chemisorption oxygen content is the highest 43.2%.The electrode prepared by the modified material is used for the detection of heavy metal ions Pb(?),Cd(?),Cu(?),the detection concentration limits are 1.043×10^-10 mol·L^-1,1.072×10^-10 mol·L^-1,1.465×10^-10mol·L^-1,respectively.The modified LDHs are grown on the carbon tube and carbon wall of the biomass material in nano-needle or flake shape.The addition of LDHs enhances the adsorption of the biomass carbon itself.The oxygen-containing functional groups on the surface of the bimetallic LDHs interact with water.The heavy metal ions are exchanged for ion exchange,making the detection limit of the modified material far lower than that of the traditional detection material.