Green Synthesis And Application Of Iron Nanoparticles And Their Composites

Dye wastewater is extremely harmful to environmental safety and biological health.Therefore,it is imperative to remove it from the water environment.In recent years,nano-iron particles have shown good performance in removing dyes due to their small particle size and large specific surface area.However,nano-iron particles are easy to agglomerate,resulting in a significant reduction in their reactivity.In addition,traditional methods of synthesizing iron nanoparticles often use toxic reducing agents,such as sodium borohydride and hydrazine hydrate.Not only is the cost high,but also secondary pollution is easily caused.Therefore,it is urgent to find a new low-cost and environment-friendly synthesis method.In view of the above-mentioned shortcomings of nano iron particles and their synthesis methods,this paper conducts relevant research.The iron nanoparticles were prepared by a novel biosynthesis based on extracted tea polyphenols.The selective removal of dyes was studied and the mechanism was discussed.On this basis,the recyclable luffa fiber loaded nano iron particles composite was further prepared and applied to the removal of dyes and the activation of persulfate to degrade pollutants.The obtained materials were characterized by XRD,SEM,FTIR,XPS,Zeta potential and UV-Vis.The main conclusions of the paper are as follows:1)Iron nanoparticles have regular spherical or ellipsoidal shape and show good selective removal for cationic dyes(Malachite green,rhodamine B and methylene blue).The removal capacity of Malachite green reaches as high as 190.3mg/g,which comforms to the presudo first order kinetic model.The possible removal mechanisms are mainly adsorption and reduction processes.2)The results of batch experiments show that the removal rate of MG by Fe Nano Ps-GT/luffa fiber composite can reach 90.23% when the temperature is 298 K,the initial concentration is 30mg/L and the reaction time is 360 min.After three cycles of use,the removal rate remained at 75.30%.In general,the prepared Fe Nano Ps-GT has excellent dye removal performance.The luffa fiber with high specific surface area can increase the adsorption of pollutants and promote the separation of Fe Nano Ps-GT.3)The degradation rate of 50mg/L golden orange II by Fe Nano Ps-GT/luffa/PS system is 97.06%.Free radical quenching experiments show that HO· and SO4·-both participate in the degradation reaction of golden orange II,among which SO4·-plays a more important role.The degradation rate of golden orange II can still reach 78.46% after the Fe Nano Ps-GT/luffa composite material is recycled for 5 times,which shows its application potential.