BioMnOx对非甾体药物氧化协同Fe(III)吸附的研究

Mechanism of degradation of non-steroidal drugs and Fe(III) adsorption by BioMnOx

摘要:

恶臭假单胞球菌(Pseudomonas Putida)可氧化Mn²⁺生成生物锰氧化物,生物锰氧化物的形成过程及其吸附氧化活性对水体中有机/重金属复合污染的控制具有重要意义.为此,通过研究生物锰氧化物对APAP（乙酰氨基酚,acetaminophen）氧化以及Fe(III)吸附探讨其吸附氧化活性的相互影响.结果表明,BioMnO_x为无定型的纳米颗粒,在形成过程中自身结构发生变化,表面由平整变为密集、突出的颗粒状,颗粒边界更为清晰,颗粒粒径从约49.9 nm长至约70 nm.BioMnO_x在形成过程中对Fe(III)的吸附发生在对APAP的氧化之前,对Fe(III)的吸附并未对APAP的氧化速率产生影响.APAP氧化降解过程和Mn²⁺氧化速率过程均符合一级动力学方程.BioMnO_x的氧化活性对APAP降解造成一定的影响.Mn²⁺质量浓度增大,可减少APAP的降解时间.GC-MS结果显示,APAP的降解途径为先被氧化为乙酰胺及对苯二酚、对氨基苯酚等苯酚类物质,继而转化为乙二酸、苯醌等更加简单的物质后最终矿化.

Abstract:

Pseudomonas putida can oxidize Mn²⁺ to produce biological manganese oxide. The formation process and the adsorption oxidation activity of biogenic manganese oxide are crucial to the control of organic/heavy metal combined pollution in water. In this paper, the interaction between acetaminophen (APAP) oxidation and Fe(III) adsorption by biological manganese oxides was studied. Results show that BioMnO_x were amorphous nanoparticles. During its aging process, its structure evolved, and the surface appearance changed from flat to dense and protruding granule. The boundary of the particles became clearer. The average particle size ranged from about 49.9 nm to 70 nm. The adsorption of Fe(III) by BioMnO_x during the formation process occurred before the oxidation of APAP, and the adsorption of Fe(III) did not affect the oxidation rate of APAP. The oxidation degradation of APAP and the oxidation rate of Mn²⁺ all fitted well with the first-order kinetic equation. The oxidative activity of BioMnO_x had certain effect on the degradation of APAP. The increased concentration of Mn²⁺ reduced the degradation time of APAP. GC-MC results show that the degradation pathway of APAP was that it was firstly oxidized to acetamide and phenolic substances such as hydroquinone and p-aminophenol, then converted into simpler substances such as oxalic acid and benzoquinone, and finally mineralized.