【作者】 王凯；

【导师】 李晓晨； 郭昌胜；

【作者基本信息】 山东农业大学 ， 市政工程（专业学位）， 2015， 硕士

【摘要】 从污水处理厂出水中去除抗生素抗性细菌(ARB)和抗生素抗性基因(ARGs)对于阻止抗生素抗性进入环境具有重要意义。先前有相关研究致力于从水溶液和污泥中去除ARB和ARGs,但都没有获得令人满意的结果。本文研究了双氧水氧化消毒技术、紫外消毒技术以及以TiO2作为催化剂的光催化氧化技术对ARB(MRSA、P.aeruginosa)和ARGs(mecA、amp C)的去除效果,以期为抗性污染传播控制提供理论参考。为了克服粉末状对抗性细菌检测和抗性基因提取产生的干扰,本文以溶胶凝胶法合成了TiO2催化薄膜并对其进行表征。XRD分析显示合成的TiO2催化薄膜为具有很高催化活性的锐钛晶型TiO2;UV-vis分析显示合成的N,F-TiO2薄膜吸收波长向红外移动,可能与合成过程中掺杂F有关;SEM分析发现TiO2颗粒为粒径小于300 nm的小球,表明N,F-TiO2薄膜具有较大的表面积,可能具有很好地光催化效能。抗性细菌去除研究显示:H2O2、UV、TiO2催化薄膜对抗性细菌均有一定的去除效果。H2O2(100 mmol/L)单独作用可使MRSA和P.aeruginosa下降2.1-2.2个数量级;UV(12 mJ/cm2)单独作用可使MRSA和P.aeruginosa下降2.2-2.5个数量级;H2O2/UV联合作用(H2O2:100 mmol/L、紫外通量:12 mJ/cm2)可使MRSA和P.aeruginosa分别下降3.77-4.56和3.67-3.78个数量级,紫外光使H2O2对抗性细菌的去除效果显著提高;UV/TiO2联合作用(紫外光通量为12 mJ/cm2)可使MRSA和P.aeruginosa分别下降5.76-5.86、5.66-5.74个数量级,UV/TiO2联合作用可以有效的提高紫外对抗性细菌去除能力。H2O2/UV/TiO2联合作用(H2O2:100 mmol/L、紫外光通量:12 mJ/cm2)可使MRSA和P.aeruginosa分别下降5.98-5.99、5.8-5.89个数量级,H2O2的加入并没有使UV/TiO2对抗性细菌的去除效果有显著的提高。抗性基因去除研究显示:H2O2、UV、TiO2催化薄膜对抗性基因均有一定的去除效果。H2O2(100 mmol/L)单独作用可使mecA和ampC分别下降0.75和0.88个数量级。UV单独(120 mJ/cm2)作用可使mecA和ampC下降2.30和1.40个数量级。H2O2/UV联合作用(H2O2:100 mmol/L、紫外通量:120 mJ/cm2)可使mecA和ampC分别下降2.95和2.17个数量级,紫外光使H2O2对抗性基因的去除效果显著提高;UV/TiO2联合作用(紫外通量:120 mJ/cm2)使mecA和ampC分别下降5.7-5.9和4.6-4.8个数量级,使INC-mecA、EXC-mecA、INC-ampC、EXC-ampC分别下降5.24、3.27、4.42、2.64个数量级,UV/TiO2联合作用可以有效的提高紫外对抗抗性基因去除能力且对胞内、胞外ARGs均具有很好的去除效果;H2O2/UV/TiO2联合作用(H2O2:100 mmol/L、紫外光通量:120 mJ/cm2)可使mecA和ampC分别下降5.7-5.9和4.6-4.8个数量级。TiO2薄膜的使用使H2O2/UV对mecA和ampC去除的效果显著提高2.7-3.4和2.7-3.2个数量级,H2O2的加入并没有使UV/TiO2对抗性基因的去除效果有显著的提高。H2O2浓度的提高均能促进抗性细菌和抗性基因的去除;H2O2易去除抗性细菌,UV易去除抗性基因;相对于P.aeruginosa和ampC,MRSA和mecA更易去除;UV/TiO2对抗性细菌和抗性基因均有很好的处理效果。更多还原

【Abstract】 Inactivating antibiotic resistant bacteria(ARB) and removing antibiotic resistance genes(ARGs) from wastewater treatment plant effluent is very important to prevent their spread into environment. Previous effo rts have been taken to eliminate ARB and ARGs from aqueous solution and sludges, however, few satisfying results have been obtained. This study investigated whether H2O2, UV and photocatalysis by TiO2 can reduce the levels of two ARGs, mecA and ampC in extracellular and intracellular forms within host ARB, methicillin-resistant Staphylococcus aureus(Gram-positive, MRSA) and Pseudomonas aeruginosa(Gram-negative, P.aeruginosa), respectively.In order to lessen the interference caused by TiO2 powder on ARB detecting and ARGs extracting, TiO2 catalytic films were synthesized by using sol- gel method. XRD analysis showed that the synthesized TiO2 thin films were crystal of anatase TiO2 with the most efficient photocatalyst than the other crystal forms; SEM analysis found that TiO2 particles in synthesied TiO2 thin films were ball and less than 300 nm revealed that synthesized TiO2 thin films had a larger surface area and mihgt have a photocatalytic efficiency.For ARB, 2.1-2.2 and 2.2-2.5 log ARB reductions were achieved by 100 mmol/L H2O2 and 12mJ/cm2UV254 fluence dose, respectively. Approximately 3.77-4.56 log MRSA reductions and 3.67-3.78 log P.aeruginosa reductions were achieved by 100 mmol/L H2O2 and 12 mJ/cm2 UV254 fluence dose respectively. 5.76-5.86 log MRSA reductions and 5.66-5.74 log P.aeruginosa reductions were achievedunder 12 mJ/cm2 UV254 fluence dose in the presence of TiO2.5.98-5.99 log MRSA reductions and 5.8-5.89 log P.aeruginosa reductions were achievedunder 12 mJ/cm2 UV254 fluence dose and 100 mmol/L H2O2 in the presence of TiO2. Matrix have little effect on ARB inactivating. P.aeruginosa was easier inactived than MRSA.For ARGs, 0.75 logmecA reductions and 0.88 logampC reductions were achieved by 100 mmol/L H2O2 and 2.30 logmecA reductions and 1.40 logampC reductions were achieved by 12mJ/cm2UV254 fluence dose. Approximately 2.95 logmecA reductions and 2.17 logampC reductions wereachieved by 100 mmol/L H2O2 and 120 mJ/cm2 UV254 fluence dose.5.7-5.9 logmecA reductions, 4.6-4.8logampC reductions,5.24 logINC-mecA reductions, 3.27 logEXC-mecA reductions 4.42 log INC-ampC reductions 2.64 logEXC-ampC reductions were achievedunder 120 mJ/cm2 UV254 fluence dose in the presence of TiO2.5.7-5.9 logmecA reductionsand 4.6-4.8 logampC reductionswere achievedunder 120 mJ/cm2 UV254 fluence dose and 100 mmol/L H2O2 in the presence of TiO2.Increasing addition of H2O2 enhanced the removal efficiencies of ARB and ARGs. H2O2 showed a better effect on ARB inactivation than ARGs removal, whereas UV irradiation showed a converse effect. MRSA was more resistant than P.aeruginosa under the same treatment condition, while the amp C was easier damaged than mecA.更多还原