Preparation Of Polymetallic Magnetic Nanomaterials For Removal Of Drug Pollutants In Water

In recent years,how to effectively remove pharmaceutical and personal care products(PPCPs)from the aquatic environment has become a global concern and research hotspot.The traditional wastewater treatment technology can't completely remove these substances,PPCPs will enter the aquatic environment through various ways.Although the residual concentration of PPCPs in the aquatic environment is usually in the range of ng/L-?g/L,the amount of PPCPs continuously input into the natural environment is relatively high.Long-term exposure to PPCPs may induce toxicological effects such as "three causes" toxicity and genotoxicity.Therefore,how to remove these substances economically and effectively is of great significance for the remediation of water pollution.Therefore,this paper planned to prepare polymetallic-based materials that could be used for water pollution remediation through the synthesis strategy of functional magnetic nano-materials,and to remove "emerging pollutants" PPCPs in water by adsorption,catalysis and other technologies,and further extended them to practical applications.The results of the three systems were as follows:1.At first,we prepared magnetic Cu₂MoS₄ composites coated with polypyrrole(Cu₂MoS₄-Fe₃O₄@PPy),and then used them to adsorb typical PPCPs.Cu₂MoS₄-Fe₃O₄@PPy exhibited synergistic effects and showed excellent adsorption performances for indomethacin(IDM) and ketoprofen(KET) with removal efficiencies of 97.1% and 88.6% at initial pollutant concentration of 10 mg/L,respectively.The adsorption of IDM and KET by Cu₂MoS₄-Fe₃O₄@PPy fitted with the Langmuir isotherm and pseudo-second-order kinetic model.Cu₂MoS₄-Fe₃O₄@PPy could be separated easily with a magnet and possessed the removal efficiency up to 83% even after eight adsorption-desorption cycles.Furthermore,the degradation of malachite green(MG)by depositing silver nanoparticles on the surface of Cu₂MoS₄-Fe₃O₄@PPy as photocatalyst showed that the function of Cu₂MoS₄-Fe₃O₄@PPy could be extended from adsorption to photocatalytic degradation.2.To further enhance the effective degradation and mineralization of pollutants,Co-doped magnetic Mn₃O₄(Fe₃O₄/Co-Mn₃O₄)was synthesized by the solvothermal method and adopted as an effective catalyst for degradation of oxytetracycline(OTC)in water.Synergistic interactions between Co-Mn₃O₄ and Fe₃O₄ not only resulted in the enhanced catalytic activity through the activation of peroxymonosulfate(PMS)to degrade OTC,but also made Fe₃O₄/Co-Mn₃O₄ easy to be separated and recovered from aqueous solution.In the presence of PMS(10 m M),94.2% of OTC(10 mg/L)could be degraded by Fe₃O₄/Co-Mn₃O₄ within 60 min.Fe₃O₄/Co-Mn₃O₄ still had a relatively stable structure and good catalytic ability after repeated cycles.Co(?),Co(?),Fe(?),Fe(?),Mn(?),Mn(?),and Mn(?)on Fe₃O₄/Co-Mn₃O₄ were identified as catalytic sites based on XPS analysis.The excellent catalytic performances of Fe₃O₄/Co-Mn₃O₄ was not only derived from large specific surface area providing abundant active centers for the activation of PMS,but also due to its charge redistribution among atoms,which accelerated the redox reaction of metal ions.The high degradation efficiency and rate constant of OTC in actual water samples indicated that Fe₃O₄/Co-Mn₃O₄ had a good practical application potential.3.Magnetic NiCo layered double hydroxides(Fe₃O₄@NiCo LDHs)were prepared as catalyst for the activation of PMS to degrade naproxen(NPX)in water.After 20 min of reaction,83.9% of NPX was removed by Fe₃O₄@NiCo LDHs(conditions:Fe₃O₄@NiCo LDHs,0.2 g/L;PMS,5 m M;NPX concentration,10 mg/L).Mechanism analysis showed that three metals(Ni,Co and Fe)catalyzed synergistically.Notably,Fe₃O₄@NiCo LDHs could be reused with good stability and the removal efficiency reached up to 78.1% even after five cycles.In addition,the high degradation of NPX in actual water samples suggested that Fe₃O₄@NiCo LDHs had a great potential in practical applications in wastewater treatment.