Synthesis Of Novel Magnetic Sulfur-doped Fe₃O₄ Nanoparticles And Their Application For Efficient Removal Of Pb???

With the rapid development of heavy-metal-related industry,the heavy metal pollution in water has emerged as a global problem.Heavy metals have strong toxicity and can hardly be degraded,moreover,they can be easily bioaccumulated and migrated,which has caused serious threat to human health and ecological environment.Therefore,its treatment and elimination of potential risks have aroused widespread concern.Aiming at the problem,a variety of treatment methods have been developed and put into practical application.Among them,the use of nano-materials as adsorbent to remove heavy metals has attracted extensive attention.In this thesis,we synthesized a novel sulfur-doped Fe₃O₄?Fe₃O₄:S?nano-material as adsorbent for Pb???in water.The as-prepared nanomaterial was characterized by TEM,XRD and FTIR,etc..The adsorption experiment on Pb???showed that the as-prepared Fe₃O₄:S NPs exhibited much better adsorption performance towards Pb???than bare Fe₃O₄ nanoparticles.Moreover,the adsorption was not significantly affected by the coexisting ions,and the adsorbent could be easily separated from water by an external magnetic field after Pb???adsorption.The molar ratio of Fe and S and the calcination temperature exhibit an influence on the adsorption performance of the nano-adsorbent.Within certain limits,the adsorption performance of the adsorbent was increased with the addition of the S amount and the rise of temperature.In addition,the removal mechanism of Pb???by Fe₃O₄:S nano-adsorbent was studied.FTIR,XPS,and XRD analysis suggested that the removal mechanism was associated with the process of precipitation,hydrolysis,and surface adsorption,in which the precipitation of PbS played a most important role in the process.According to the experimental results,the optimum synthesis condition of Fe₃O₄:S nano-adsorbent was determined:the molar ratio of iron to sulfur source was 1:5,and the calcination temperature was 300°C.The nano-adsorbent was also applied to the treatment of actual industrial wastewater and showed a favorable adsorption performance,which demonstrated its potential in practical wastewater treatment.