诺氟沙星水溶液的湿式氧化分解及其产物的生成途径

Wet-oxidized decomposition of norfloxacin solution and its product formation pathways

以诺氟沙星(NOR)水溶液作为抗生素废水的代表,在湿式氧化的环境中考察其分解规律与产物生成途径,为含抗生素废水的湿式氧化处理提供方法基础。在温度为473～513 K,压力为3 MPa,NOR初始浓度约为500 mg/L,H2O2投加量为0和32 200 mg左右以及停留时间为10～60 s的条件下进行湿式氧化实验,以诺氟沙星去除率(NORR)和TOC去除率(TOCR)作为指标评价处理效果,以降解产物LC/MS分析结果作为依据推断了其分子结构及生成途径。结果表明:湿式氧化法能高效氧化分解水中NOR,H2O2存在时,过程表现为氧化反应,在较低反应温度和较短停留时间条件下便可实现分别高达99.9%和62.0%以上的NORR和TOCR,而没有加入H2O2的热裂解反应其NORR值和TOCR值仅分别为35.9%和4.1%;增加温度和延长停留时间有利于提高TOCR的值;在氧化过程中主要产生了9种分解产物,分子式分别为C16H18FN3O5、C16H18FN3O3、C8H10FN3O及C8H10FN3等,推测为由羟基自由基参与氧化分解NOR分子主体结构中的哌嗪环和萘啶环所致。

To investigate the effect of wet oxidation of norfloxacin solution and its product formation during decomposition,thus providing reference for wet oxidation of such antibiotic wastewater,reaction experiments were carried out under the conditions of temperature being 473～513 K,pressure being 3 MPa,initial concentration of NOR being about 500 mg/L,H2O2 quantity being 0 or about 32 200 mg and residence time being 10～60 s,using NORR and TOCR as the evaluation index and LC/MS analysis of decomposition products as the basis.The results showed that NOR could be decomposed efficiently,for example,although at low temperatures and short residence time,NORR and TOCR reached 99.9% and 62.0%,respectively through oxidation reaction in the presence of H2O2,while they reached only 35.9% and 4.1% through pyrolysis reaction in the absence of H2O2.TOCR increased with the increases in the temperature and residence time.Nine major decomposition products,with molecular formula as C16H18FN3O5,C16H18FN3O3,C8H10FN3O,C8H10FN3 and so on,were observed in the oxidation process,which were formed through the decomposition of the piperazinyl substituent or naphthyridine moiety in NOR by hydroxyl radicals.