Production Of Hydroxyl Radicals By UV/O₃ Advanced Oxidation Process And Its Application Study In Medical Fabric Washing

This paper is dedicated to explore the UV/O₃ advanced oxidation process to produce hydroxyl radicals?·OH?washing at low temperature,the sterilization and disinfecting effects on medical fabrics are evaluated and it can effectively sterilize and disinfect,which is of great practical significance to improve the energy utilization rate.In this paper,the optimal process of producing·OH by UV/O₃ is studied,and the effects of p H,UV wavelength and intensity on·OH production are investigated.Using Salicylic Acid as the·OH capturing agent.The hydroxylation products,2,3-dihydroxybenzoic acid and 2,5-dihydroxybenzoic acid produced by the reaction of Salicylic Acid and·OH are detected by High Performance Liquid Chromatography UV detector.The amount of·OH production is indirectly obtained.After optimizing the process production of·OH,the bacterial clothes of Staphylococcus epidermidis,Escherichia coli and Staphylococcus aureus are washed and evaluated.The results are as follows:1. Detection conditions of Salicylic Acid and its hydroxylation products by High Performance Liquid Chromatography UV detector are:C18 reversed phase column,mobile phase is methanol:0.2%phosphoric acid aqueous solution=50:50,flow rate is 1.0 m L/min,the column temperature is 35?,the detection wavelength is 320nm.There is a good linear relationship between the peak area and concentration of Salicylic Acid and its hydroxylation products.The linear correlation coefficient is above 0.997,which can satisfy the test requirements.2. In UV/O₃ process,UV wavelength is 254 nm,UV intensity is 200 W,ozone gas flow is 20 L/min,pump flow is 1 L/min,water temperature is 25?,reaction time is 20 min.At the condition of p H 4.0,7.0,10.0,the amount of·OH generated is 27.61?mol/L,87.47?mol/L,42.84?mol/L·OH.The result shows that p H has significant effect on the production of·OH.The optimal p H of·OH production is 7.0;when the other reaction conditions are same,different UV wavelength makes the amount of·OH little difference.The result shows that under existing conditions,the UV wavelength has no significant effect on the production of·OH;When the other reaction conditions are same,the UV intensity is changed.It is found that 200 W can generate·OH 2.0times more than 100 W.The result shows that the UV intensity has a significant effect on the production of·OH.The optimal process for the production of·OH by UV/O₃ process is p H 7.0,UV wavelength is 254 nm,UV intensity is 200 W,ozone gas flow is 20 L/min,pump flow is 1 L/min,water temperature is 25?.3. The bacterial clothes of Staphylococcus epidermidis?10⁴CFU/100cm²?, Escherichia coli?10²CFU/100cm²?and Staphylococcus aureus?10²CFU/100cm²?are washed by the optimal process of UV/O₃process.After 5 min washing,the bactericidal rate of Staphylococcus epidermidis is 99%,Escherichia coli and Staphylococcus aureus are not detected;after 10 min washing,the bactericidal rate of Staphylococcus epidermidis is 99.9%.It can reach the standard of cleaning textiles after 5 min washing;it can make the bacterial clothes more cleaner and safer after 10 min washing.