Investigation Into Mechanism Of Green Synthesis Of Iron Nanoparticles By Reducing Component Of Sunflower

Fe nanoparticles have been regarded as an excellent type of environmental functional material with enormous surface area,outstanding reducing property and high reaction activity,which has been widely used in the field of environmental restoration.Plant biomass-based iron nanoparticles preparation methods have attracted more and more researchers'attention due to their low cost,wide source of raw materials,and friendly to environment.However,the size,morphology,and composition of the nano-iron prepared by different plants are different.The mechanism of reducing components in the process of preparing nano-iron from the green extract of the plant has not yet been clarified,and further research is needed.Based on the above background,this study took sunflower leaves as the research object.First,the content of the representative reducing components in sunflower leaves was measured.The sunflower leaf extract was used as a reference,and the representative reducing components were combined for the preparation of nano iron.And then measure the parameter changes before and after the reaction process,at the same time,investigate the reactivity of the prepared nano-iron to the U?VI?solution,and finally analyze by different characterization techniques to explore the mechanism of action of reducing components in the preparation of nano-iron.In this study,the content of representative reducing components?chlorogenic acid,polyphenols,flavones,and reducing sugars?in sunflower leaves was measured.The results showed that the order of the representative reducing components in sunflower leaves was flavonoids>Polyphenols>reducing sugars>chlorogenic acid.Changes in iron content before and after the process,changes in pH and redox potential,and changes in the content of different reducing components were used to determine the key components that reduce and protect the sunflower during the preparation of iron nanoparticles.The results show that,except that the reducing sugar single-component solution could not successfully prepare iron nanoparticles,the combined combined solutions of the other reducing components can achieve the preparation of iron nanoparticles,further indicating that the reducing component?chlorogenic acid,Polyphenols,flavonoids?containing a catechol structure,are the active ingredients that play a key role in the preparation of iron nanoparticles by sunflower.During the synthesis of nano-iron,the effects of each reducing component on the formation of nano-iron are different:the activities of chlorogenic acid and polyphenols mutually inhibit;Polyphenols can promote the activity of flavones,and flavones have no effect on the activities of polyphenols;reducing sugars can inhibit the activity of chlorogenic acid and polyphenols,and have no effect on the activities of flavones.Furthermore,the prepared iron nanoparticles particles were used to remove U?VI?in an aqueous solution to compare the reactivity.Under the treatment conditions,the amount of iron nanoparticles added was 0.05 g,and 25 ml of U?VI?with an initial concentration of 10 mg/L)Solution,the initial pH value is 5.0,the reaction temperature is room temperature,and shake at 180 rpm for 90 min.Under these conditions,the iron nanoparticles particles prepared by the combined solution of chlorogenic acid and reducing sugar have the highest reactivity,and the removal efficiency of U?VI?is 99.45%.Chlorogenic acid,polyphenols,flavonoids,reduction The iron nanoparticles particles prepared by the four-component sugar solution had low reactivity,and the removal efficiency of U?VI?was79.26%.The kinetics of the removal reaction process was studied.This process conforms to a quasi-second-order kinetic model.TEM,EDS,XRD,XPS and other technologies were used to characterize and analyze the iron nanoparticles particles prepared from sunflower leaf extract and the prepared combination solution.It was found that the iron nanoparticles particles made from sunflower leaf extract and the prepared combination solution were amorphous.Near-spherical particles,with an average size of about 50-100nm,exist mainly in the form of Fe₃O₄ and FeOOH,and the surface is covered with active molecular organic matter,oxygen-containing functional groups such as phenolic hydroxyl and carboxyl groups play a reducing and protecting role.Among the prepared iron nanoparticles particles,the four-component combination solution of chlorogenic acid,polyphenols,flavones,and reducing sugars had the lowest iron content,which was 5.24%.The iron content was the highest at 11.1%,there is a positive correlation between the iron content of nano-iron particles and the reactivity of U?VI?.