Preparation Of Iron Carbon Composite And Its Catalytic Degradation Of P-nitrophenol

With the rapid development of modern industry,the discharge of industrial wastewater has increased sharply.Among them,p-nitrophenol（p-NP）is a common toxic pollutant in wastewater.Catalytic reduction of p-NP to p-aminophenol（p-AP）is a suitable pretreatment process.However,most of the current research on the catalytic reduction of p-NP is to use noble metal catalysts to reduce it to p-AP,and p-AP still has the dual toxicity of aniline and phenol,which may also bring huge safety hazards.Therefore,in this paper,chemically active Feis loaded on glucose-based carbonaceous materials to prepare a catalyst（GC/Fe）,sodium borohydride（NaBH₄）is used as a reducing agent,and the performance of GC/Fecatalyzed by NaBH₄to reduce p-NP is investigated,and The product p-AP is oxidized and degraded.The main content and results are as follows:（1）Using glucose as the carbon precursor and FeCl₃·6H₂O as the iron source,GC/Fewas prepared by a slow pyrolysis method,and the catalyst was microscopically characterized by SEM,XRD,XPS and other characterization methods.The results show that Fein GC/Fehas a good spherical structure and is evenly dispersed on the surface of carbonaceous materials.The GC/Feprepared under the conditions of a calcination temperature of 1000℃and a carbon-to-iron mass ratio of 1:1 showed good catalytic activity in the experiment of catalytic reduction of p-NP.（2）GC/Fewas used to catalyze the reduction of p-NP by NaBH₄to study its catalytic performance.The results show that the initial pH of the reaction solution,the initial concentration of p-NP,the dosage of GC/Fe,the dosage of NaBH₄,and the reaction temperature have a certain effect on the catalytic reduction reaction.The reaction rate increases with the increase of GC/Fedosage and reaction temperature,and decreases with the increase of NaBH₄dosage,p-NP initial concentration and pH.The activation energy of the reaction is 12.97 k J·mol^-1.In addition,the reaction process is non-spontaneous and endothermic.The catalyst has good cycle stability,and the removal rate after 8 times of repeated use is also above 90%.According to kinetic studies,the catalytic reduction reaction mechanism conforms to the L-H mechanism.（1）（3）Based on the reaction conditions of the catalytic reduction experiment of p-NP,molecular oxygen is used as the oxidant to oxidatively degrade p-AP.The results show that the GC/Fecomposite material can activate molecular oxygen to successfully degrade p-AP.The degradation rate of COD reaches 58.9%and the degradation rate of TOC reaches42.3%after 240 min of reaction.The initial pH of the reaction solution,the initial concentration of p-AP,the amount of catalyst added and the amount of aeration have a certain effect on the catalytic oxidation reaction.Within a certain range,the removal rate of p-AP increases with the increase of the catalyst dosage and the aeration rate,but excessively increasing the aeration rate will inhibit the removal of p-AP;with the initial concentration of p-AP and As the pH increases,it decreases.Combining with the principle of Fe⁰activated molecular oxygen,the research status of p-AP oxidative degradation,the ultraviolet spectrum of p-AP oxidative degradation,COD and TOC removal rate,the degradation mechanism of p-AP is discussed.The results show that Fe0 produces strong oxidizing·OH and·O₂^-through the two-electron and single-electron molecular oxygen activation pathway,and oxidatively degrades p-AP to generate low-molecular-weight organic acids and other easily oxidizable substances,which are finally ore Converted into H₂O and CO₂.