The Preparation Of Novel Magnetic Carbon Materials And Their Application In The Heterogeneous Fenton-like System

Organic synthetic dyes are widely used in textile, paper, plastics, leather and food industries. Methylene blue is a phenothiazine dyes. It can cause eye burns and permanent damage to human and animals eyes. On inhalation, it can give rise to short periods of rapid or difficult breathing while ingestion through the mouth produces a burning sensation and may cause nausea, vomiting, profuse sweating, mental confusion and methemoglobinemia. Therefore, removing MB dye from wastewater is an issue of great concern. Because synthetic dyes contain one or more benzene rings that do not easily decompose. Recently, advanced oxidation process (AOPs) have been proposed as effective method for wastewater treatment as AOPs are very powerful way to destroy a wide range of tough organic contaminants. AOPs can produce hydroxyl radical (HO-) which is a strong oxidant. Among AOPs, Fenton system is an attractive treatment for the effective decolourisation and degradation of dyes because of its low cost and nontoxicity. Magnetic heterogeneous Fenton’s reagent can be efficiently separated and recovered by the applied magnetic field. Recently more and more attention have been attracted by Carbon-based materials because its ease of functionalization, its reduction of the magnetic coupling between individual magnetic nanoparticles and its stability in acid or base as well. The major drawback of the Fenton system was the accumulation and precipitation of Fe3+, which could further result in the decline of reaction rates. Hydroxylamine (NH2OH) was adopted as a reductive chemical material to reduce Fe3+. Therefore, this thesis adopted different method to synthesize novel magnetic carbon materials, and applied them in the heterogeneous Fenton-like system for degradation of methylene blue. The main research content is as follows:1. RGO/CoFe2O4 composite:synthesis and applications on Heterogeneous Fenton-Like OxidationA one-pot solvothermal reaction was used to prepare CoFe2O4/Reduced graphene oxide (RGO) composite using graphene oxide, Fe(acac)3 and COCl2·6H2O as starting materials. Graphene oxide was reduced to graphene and the CoFe204 particles were concurrently grown on the carbon basal planes under the conditions generated in the solvothermal system. Monodisperse CoFe2O4 nanoparticles of consistent shape were uniformly dispersed on the graphene. Samples were characterized by transmission electron microscopy, X-ray crystallography, X-ray photoelectron spectroscopy, Brunauer-Emmett-Teller surface area measurement, and vibrating sample magnetometry. Such CoFe2O4/RGO composite was used as an efficient heterogeneous catalyst to degrade Methylene blue (MB) in aqueous solution by a Fenton-Like reaction. Catalytic testing showed CoFe204/RGO composite exhibited much better catalytic activity than CoFe204, which suggests RGO plays an important role in CoFe2O4/RGO composite for the decomposition of MB. Addition of NH2OH enhanced the reaction rates. Magnetic material also has a good stability. Therefore, CoFe2O4/RGO composite are applicable to be a green heterogeneous Fenton reagent in the field of water pollution control engineering.2. The preparation of magnetic carbon materials from Fe-MOCPs and their application in the Fenton-like systemWe report a method to fabricate magnetic carbon materials which are derived by metal-organic coordination polymers (MOCPs). Two kinds of MOCPs were prepared through solvothermal synthesis and then calcinated into Fe3O4@C and CuFe2O4/Cu@C magnetic carbon materials at a temperature tested by thermogravimetric analysis. The materials were characterized by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, element analysis, inductively coupled plasma, Brunauer-Emmett-Teller surface area measurement, and vibrating sample magnetometer Analysis. The as-prepared materials were used as heterogeneous Fenton’s reagent with the addition of H2O2 for degradation of methylene blue (MB). It was found that materials could effectively catalyze H2O2 to generate hydroxyl radicals (·OH). And due to their magnetism, materials can be easily separated from wastewater to realize the repeatability. Both of materials had good stability. It showed that Fe3O4@C and CuFe2O4/Cu@C as new kind of magnetic carbon materials is expected to be applied to the removal of organic pollutants in wastewater.