Preparation Of Two Iron Based Catalysts And Their Catalytic Performance For Degradation Of Organic Pollutants

The rapidly growth of modern industry has caused serious water pollution problems,and water environment is closely related to the survival and development of people.Therefore,Water pollution has been widely concerned by all walks of life.Among the many current water pollution treatment technologies,the advanced oxidation technology includes Fenton oxidation and photocatalytic oxidation and ozone oxidation and ultrasonic oxidation technology.The advanced oxidation technology is popular because of their strong oxidation and clean products.At the same time,iron is one of the huge metal elements in the earth's crust,playing a vital role in the field of environmental catalysis.Iron-based materials have the advantages of convenient preparation,no pollution to the environment,high activity and relatively low price,so they have very good practical application value.Today,the situation in which the natural environment is polluted is getting worse and worse,the development and research of new iron based materials have become one of the hot topics in the field of environmental and material research.In this dissertation,we designed and prepared magnetic recoverable nano CuO/Fe₃O₄ and Fe₃O₄/MIL-101 complexes,respectively,which are used treatment of pollutants in the environment in advanced oxidation system.The specific content of the inquiry is as follows:?1?Nano CuO/Fe₃O₄ composites were prepared by calcining?600??with K₃[Fe?CN?₆]and Cu?NO₃?₂·3H₂O as precursor,and applied to Fenton-like reaction.XRD,SEM and XPS analysis showed that the CuO/Fe₃O₄ composites had a uniform spherical particle morphology,with a particle size of about 20 nm.The nano CuO/Fe₃O₄ composites could effectively activate the deep mineralization of bisphenol A?BPA?through the sulfates?PMS?.Under specified reaction conditions(BPA concentration 20 ppm,PMS concentration 0.3 mmol?L^-1,catalyst dosage 0.3 g?L^-1,pH₀ value of 6.0),the CuO/Fe₃O₄-PMS system yielded a pollutant removal of 100%?in 10 min?,and a mineralization rate of 97%?in 30 min?.Both the degradation efficiency and the reaction rate is far higher than that of the single CuO and Fe₃O₄system,showing a significant synergistic effect.Free radical quenching experiments and electron paramagnetic resonance spectroscopy showed that the catalytic activation of the CuO/Fe₃O₄ composites produced by sulfate for sulfate radical?SO₄·^-?and hydroxyl radical?·OH?as main active species.The catalytic mechanism of sulfate activation by the CuO/Fe₃O₄ composite for the degradation of bisphenol A was proposed as follows:PMS reacts first with copper and iron ion on the CuO/Fe₃O₄surface to generate SO₄·^-and Cu²⁺/Cu⁺radicals;the redox potential of Cu²⁺/Cu⁺is more negative than that of Fe³⁺/Fe²⁺,the generated Cu⁺reacts with Fe³⁺,leading to their conversion into Cu²⁺and Fe²⁺;SO₄·^-free radicals react with H₂O further to generate·OH radicals;finally,SO₄·^-and·OH will degrade and mineralize the organic pollutants.?2?Micro-scale Fe₃O₄@MIL-101 particles were prepared by Hydrothermal method with Fe₃O₄,terephthalic acid,FeCl₃·6H₂O and N,N-dimethyl formamide?DMF?as precursors.Fe₃O₄@MIL-101 were used for catalytic activation of H₂O₂ to degrade environmental organic pollutants.Azo dye rhodamine B was used as target pollutant,and its sorption and Fenton-like degradation were investigated in detail.The results showed that in the new heterogeneous Fenton system with optimized condictions(catalyst load 0.3 g?L^-1,H₂O₂ concentration 30 mmol L^-1,30?,initial pH 6.0,RhB concentration 0.03 mmol?L^-1),reaction for,the RhB removal was 100%in 15 min for the oxidation after a 30 min pre-adsorption.The rapid degradation of RhB was attributed to the heterogeneous Fenton-like activity of the Fe₃O₄@MIL-101 particles.