Study On The Degradation Of Chloramphenicol By Different Oxidation Systems Catalyzed By Pipeline Growth Ring

Chloramphenicol is a new type of pollutant.Because it can induce drug-resistant bacteria,it is a very serious potential threat whether to the water environment or human health.Trace amounts of chloramphenicol will enter the water body,pollute the source water,and pose a huge risk to drinking water safety.The structure of the growth ring in the water supply pipeline includes sediment,rust,clay,etc.The main components are goethite,lepidocrocite,silica,etc.,because it contains iron oxides,it can be used as a Fenton-like catalyst.In this paper,the growth ring was selectd as the research object in an actual water supply pipe section of a city in Heilongjiang Province,its composition was analyzed,and its morphology,pore size and surface characteristics were characterized.Then,the actual growth ring was used as a catalyst,and hydrogen peroxide（H₂O₂）,potassium persulfate（PMS）,H₂O₂/PMS were used as an oxidant to form a catalytic oxidation system to degrade chloramphenicol.The effects of different oxidation systems on the degradation of chloramphenicol were investigated and compared.At the same time,different components of the growth ring were added on the basis of the catalytic oxidation system to investigate the effect of different components on the removal of chloramphenicol.Finally,the kinetics of the actual growth ring catalyzing the degradation of chloramphenicol was analyzed,a degradation model was constructed,and its reaction mechanism was explored.When hydroxylamine hydrochloride is added to the catalytic oxidation system,the removal rate of chloramphenicol is greatly improved due to the promotion of the Fe³⁺and Fe²⁺circulation,so an appropriate amount of hydroxylamine hydrochloride is added to the system in this paper.The additional addition of different components in the system has different effects on the removal of chloramphenicol.Ferric oxide can increase the final degradation of chloramphenicol,ferrous sulfide can increase the initial degradation rate of chloramphenicol,and silica can also promote chloramphenicol degradation;alumina and manganese dioxide inhibit the removal of chloramphenicol and hinder the degradation of chloramphenicol.The best combination of different components to degrade chloramphenicol is 5mgFeS+10mg Fe₃O₄+20mgSiO₂.The Fenton-like system with the actual growth ring as the catalyst has a better removal effect of chloramphenicol.After 2 hours,the removal rate of chloramphenicol reaches 78.97%.Different influencing factors were analyzed to get the best experimental conditions.It was found that the H₂O₂/PMS double oxidation system had the highest removal rate at 80.08%through the experimental comparison of the degradation of chloramphenicol by different oxidation systems,and the catalytic oxidation ability of the two oxidants was stronger than a single oxidant.The degradation reaction of chloramphenicol in the Feonton-like system with the actual growth ring as a catalyst is a second-order reaction,the PMS system is a first-order reaction,and the two stages of the double oxidation system are both pseudo-first-order reactions.The active substances are a large amount of·OH and a small amount of SO₄^-·,which can remove chloramphenicol through the oxidation of free radicals.