Pre-adsorption/fenton-like Oxidation Of 2,4-dichlorophenol By Green Synthesized Iron-based Nanoparticle

Recently,the removal of persistent organic pollutant using nanoscale iron-based materials has become the leading issues in the environmental remediation,in which green synthetic iron-based nanoparticles used for remove organic pollutant are of concerned due to ite low cost and environmentally friendly.The main objective of this study is to degradation of 2,4-dichrolophenol(2,4-DCP)by green synthesized iron-based nanoparticle(Fe NPs).Firstly,the particle size,morphology and activity of Fe NPs by different leaf extracts were compared and analyzed.Combined with SEM,FTIR,XPS EDS and other characterization results showed that Fe NPs using Euphorbia cochinchensis leaf extracts were mainly spherical,with excellent stability and dispersion,the diameters in range of 20-50 nm,the decolorization efficiency of methylene blue is the highest,which was 99.3%.Therefore,Euphorbia cochinchensis leaves was selected as raw material for Fe NPs in a variety of leaves.Secondly,the activity components as reducing agent of Euphorbia cochinchensis leaf extracts and the composition of Fe NPs were further studied,and then the removal of 2,4-DCP by Fe NPs in aqueous solution.The experimental results indicated that there are phenolic compounds,liquid esters,alcohols and other organic substances as reducing agents in synthesis process,Fe NPs are composed of iron oxide with different valence states,and then a possible synthesis mechanism and process were proposed.Fe NPs were used as adsorbent and catalyst for degradation of 2,4-DCP,respectively.Results demonstrated that the removal efficiency of single adsorption or single Fenton-like oxidation of 2,4-DCP was lower than pre-adsorption/Fenton-like oxidation sequential process,the degradation efficiencies of the three methods were 20.6%,50.9%and 64.0%,respectively.Finally,an integrated technology based on the pre-adsorption and Fenton-like oxidation sequential process to remove 2,4-DCP in aqueous solution by Fe NPs using Euphorbia cochinchensis leaf extracts as both adsorbent and catalyst was researched.In addition,several operation parameters including the reaction temperature,initial pH,initial concentration of 2,4-DCP and H2O2 concentration on the degradation of 2,4-DCP were investigated,and the mechanism of the degradation of 2,4-DCP was proposed.The results of condition experiments showed that the reaction temperature,initial concentration of 2,4-DCP,initial pH and the dosage of H2O2 had different effects on the degradation efficiency,the combination of Fe NPs and integrated technology has improved the limitation of single Fenton-like oxidation only for strong acidic solution.Kinetic studies indicated that the adsorption process was spontaneous and fitted well to the pseudo-second order model in the pre-adsorption/Fenton-like oxidation integrated technology,the pseudo-first order model was the most suitable for describing the Fenton-like oxidation.GC-MS was carried out to detect the intermediates and the final products of 2,4-DCP degradation.Above result indicated that pre-adsorption/Fenton-like oxidation based on the green synthesis of iron-based nanoparticles is used for degradation of chlorophenols.