The Confined Construction Of Multicomponent Iron Nanocatalyst And Their Application In Fenton Reaction

In recent years,increasing variety and amount of traditional and emerging contaminants are discharged into the environment.Most of these contaminants are refractory and toxic even in trace concentrations,which cannot be well treated using conventional biological and physical methods and pose risks to human health and ecological systems.Fenton-like have been widely accepted as effective technologies to destruct these compounds,especially for high concentration,hazardous,nonbiodegradable or recalcitrant chemicals.The Fenton-like oxidation process is based on the oxidation of highly active substances(such as·OH,·O2-,and 1O2),which causes the target pollutant to completely degrade or be converted into less harmful intermediates.However,due to excessive oxidant consumption,catalyst dissolution,and short active species lifetime(<10 ms)in Fenton-like process,which lead to the defects of Fenton-like oxidation process,such as low reaction rate,secondary pollution and high cost,limit its development.limit their development.When the oxidation reaction is controlled in the confined nanospace through the reasonable design of catalyst,the precise regulation of catalytic reaction can be achieved under the coordination of the nanoconfinement effect,and the reaction rate and activity can be increased.In this paper,based on the confinement effect,a series of composite catalysts with iron based catalysts as the main catalyst in the confined space was designed and successfully prepared,which had the catalytic performance of highly efficient activated oxidants to degrade of organic pollutants.The specific research content is as follows:1.The non-contact Fe2O3-Au@SiO2 nanocomposites were designed and successfully prepared.The Fe2O3 nanowires and Au NPs were wrapped in SiO2 shell with a non-contact manner,and the relative position of Fe2O3 and Au NPs were precisely controlled.As an efficient H2O2 activator toward catalytic oxidation of toxic organic contaminants,the Fe2O3-Au@SiO2 represent high activity in the photo-Fenton degradation of 2-CP,4-CP,ciprofloxacin,BPA and so on.The degradation rate of 2CP reached 87%within 15 minutes,with the reaction rate constant of 0.1029 min-1,was 3.2 times of Fe2O3-Au@SiO2-no-cavity.At the same time,the Fe2O3-Au@SiO2 with void diameter of 10 nm represented highest activity.·OH,·O2-,and h+ are the main active species.For non-contact Fe2O3-Au@SiO2,the LSPR effect of Au NPs and high utilization efficiency of light greatly improved catalytic performance,and endow promising applications in complex and actual water treatment.2.Design and synthesis of Fe0 nanoparticles in carbon nanocube(Fe0@C),as a catalyst with high activity and high stability,through the activation of PMS to complete the degradation of organic pollutants.The polydopamine shell was coated on the surface of Prussian blue,and stable carbon cubic shell coated the well dispersed Fe0 were obtained through high-temperature carbonization and reduction treatment.As the wrapped carbon layer provided a confined space for Fe0,it can effectively prevent the aggregation and dissolution of Fe0 particles.Fe0@C had a large specific surface area,can provide more active sites for the catalytic reaction process,and promote the adsorption and transfer of pollutants,greatly improve the catalytic activity of PMS activated degradation of organic pollutants.For the Fe0@C,the degradation rate of BPA can reach 100%within 5 minutes,Fe0@C had better catalytic performance than the pure Fe0 nanoparticles(4.2fold).The degradation rate of various pollutants,such as chlorophenol,ciprofloxacin,carbamazepine,atrazine,and sulfamethoxazole,reached over 90%within 60 minutes.At the same time,the oxidation reaction mechanism was mainly affected by the combination of free radical(SO4·-,·O2-,·OH)and non free radical(1O2).This work provided a new idea for the design,synthesis,and application of zero valent metal catalysts.