Preparation And Properties Of Nano Fe/Co Fenton-like Catalyst

The water in China has been generally polluted by antibiotics.However,it cannot be completely and effectively degraded by activated sludge biological treatment method.The Fenton-like processing technology has the same effect as the Fenton processing technology in dealing with toxic and harmful and other refractory organics.However,the Fenton-like treatment techniques have the disadvantages of low catalytic activity,unstable active components and easy precipitation.Therefore,the preparation of Fenton-like catalysts with high catalytic performance,wide pH application range,and good stability is an important direction for the current Fenton-like technology research.In order to prepare nano-iron-cobalt-based Fenton-like catalysts with good degradation effect,wide pH application range and good stability on tetracycline hydrochloride,nanometer Fe/Co-Fenton-like catalysts were prepared by liquid-phase reduction method and impregnation-calcination method,respectively.It utilizes the synergy between Fe/Co to strengthen the catalytic activity and stability.At the same time,it uses the Lewis acidity of cobalt to create favorable Fenton-like activity environment and widen the applicable range of catalyst pH.The main research contents of this dissertation are as follows:1)Taking the removal rate of tetracycline hydrochloride and the physical structure of the catalyst as reference,the influence of the preparation factors on the structure and performance of the catalyst is analyzed and optimized.2)Using tetracycline removal rate as indicator,explore the influence of reaction factors such as initial pH value,hydrogen peroxide dosage,initial concentration of tetracycline hydrochloride on catalytic performance and repeated reuse performance,and explore the stability of the reaction system on the stability of the catalyst.Impact.3)Preliminary exploration of the mechanism of catalyst pH broadening and possible degradation pathway of tetracycline hydrochloride.The main conclusions of this paper's research are as follows:1.Preparation of nanocatalysts by liquid phase reduction and impregnation-calcination methods can reduce the particle size and extend the specific surface area of the catalyst.2.The use of nano-Fe/Co catalysts to degrade tetracycline hydrochloride has a good catalytic effect and broaden the scope of application of the catalyst:the degradation rate of tetracycline hydrochloride in the pH range of 3-9 is 87.2%to 91.7%,and the maximum Fe precipitation is 0.18 mg/L and Co precipitated was 0.98 mg/L.The degradation rate of tetracycline hydrochloride in the pH range of 5-9 is 84.6%to 86.6%,the maximum Fe precipitation was 0.28 mg/L,and the maximum Co precipitated is 1.00 mg/L.3.According to experiments and related literatures,cobalt element promotes the Fe²⁺/Fe³⁺cycle by maintaining the concentration of Fe³⁺in the catalyst,increases the catalytic activity of the catalyst in a neutral environment,and broadens the range of pH of the catalyst;the degradation pathway of tetracycline hydrochloride:1)Tetracycline hydrochloride forms a stable product through hydrogenation of carbonyl groups?m/z447.6?,2)loses amino group and N-methyl group,or dehydroxylation forms an intermediate product?m/z 400?,etc.,and is broken or removed via a carbon-carbon single bond.Hydroxyl products?m/z 275.2,m/z 147.2,m/z 149.3,etc.?,which undergo ring-opening degradation into small molecules and mineralization,crack carbon-carbon single bonds to undergo ring-opening reactions to produce intermediate small molecules?m/z 275.2,m/z 147.2,m/z 149.3,etc.?and then undergo ring-opening degradation into small molecules or mineralization.