Characteristics Of Polydopamine Copper Phosphate Nanoflowers For Deep Purification Of Lead-Contaminated Water

As the industrialization process continues to accelerate,the form of heavy metal pollution in wastewater is becoming more and more complex.The efficient remediation of the diverse heavy metal pollutions in aquatic environment is tricky by traditional treatment methods.In this work,a sort of hybrid nanoflower materials integated poly-dopamine with copper phosphate(PDA-Cu3(PO4)2 NFs)were fabricated for effective adsorption of Pb(II)and decomplexation of Pb-EDTA.The adsorption behavior of Pb(II)and decomplexation peformacne of Pb-EDTA by the synthensized PDA-Cu3(PO4)2 NFs were investigated to shed light on the mechanisms of Pb(II)adsorption and catalytic decomplexation,respectively.The main research work is described in detail as follows:(1)The PDA-Cu3(PO4)2 NFs was synthesized via in-situ self-assemble method,which was based on the growth of copper-phosphate mediated by polymerization of dopamine.The moropholgy of obtained sample was characterized by scanning electron microscopy(SEM),transmission electron microscopy(TEM),Brunauer-Emmett-Teller(BET)and other techniques,exhibiting the petal-like muliti-level structure with an average size of 5-15μm.Moreover,X-ray diffraction(XRD),Fourier transform infrared spectrum(FTIR)and Raman spectra unveiled the physichemstrical structure of PDA-Cu3(PO4)2 NFs,of which skeleton is copper-phosphate and surface is convered by PDA with aboudant-NH2 and-OH groups.(2)The effect factor experiments,such as p H value,reaction temperature,coexisting ions et.al,were conducted to invetigate the adsorption performance of Pb(II)ions by PDA-Cu3(PO4)2 NFs.It is revealed that 96.1%of Pb(II)was eliminated by PDA-Cu3(PO4)2 NFs at p H 5.0,which is attribution to the active surface adsorption caused by-NH2 and-C-OH groups,along with the replacement of copper-phosphate skeleton.The Pb(II)removal would reach the adsorption equilibrium within 60 min,which is a endothermic process and insensitive to the interruption of coexisting impurities.Excellent remediation of simulated industrial wastewater(6000 L wastewater/kg adsorbent)was realized by a continuous filtration adsorption device with PDA-Cu3(PO4)2 NFs as adsorbent that still presented 88.9%of Pb(II)removal even after 15 times recycling.(3)The decomplexation-adsorption performance of Pb-EDTA was investigated in the PDA-Cu3(PO4)2 NFs/H2O2 system,which showed effective removal of Pb-EDTA(87.3%)after 3 h reaction at p H 7.0.The reactive oxygen species(ROSs)generated in the PDA-Cu3(PO4)2 NFs/H2O2 system was determined by the radicals masking experiment conbined with electron spin resonance(ESR)analysis,revealing that singlet oxygen(~1O2),hydroxyl radicals(·OH)and oxygen vacancies(OVs)were the dominant ROSs for the decomplexation of Pb-EDTA.Based on the XPS analysis,the catalytic decomplexation caused by Cu(I)/Cu(II)redox cycle combined with surface adsorption is the Pb-EDTA removal mechanism in the PDA-Cu3(PO4)2 NFs/H2O2 system.