【作者】 张斌；

【导师】 张平；

【作者基本信息】 中南林业科技大学 ， 环境工程（专业学位）， 2025， 硕士

【摘要】 四环素和苯酚是废水中典型的有机污染物,传统处理手段虽有不错的处理效果,但存在反应条件苛刻、去除不彻底等缺点。锰元素是一种活跃的变价重金属,其氧化物是重要的天然氧化剂,生物锰氧化物比天然锰氧化物具有更好的氧化活性。Fe3+也同样具备氧化性,且能增强特定污染物的去除。因此研究锰氧化菌氧化生成的生物锰氧化物,并将其与Fe3+组配成复合材料来处理废水中的四环素和苯酚,是一种高效的水处理技术。本研究在制备材料的基础上,考察了环境因子对材料去除四环素和苯酚的影响作用,并结合SEM、XRD、FT-IR、XPS及液-质联用等手段,分析其可能作用机理,同时分析了材料在实际废水中应用的可能性,主要研究结果如下:(1)利用实验室已有的一株具有锰氧化活性的缺陷短波单孢菌(Brevundimonasdiminuta)(简称 X1),与Mn2+、Fe3+组配,成功制备成 了生物源铁锰氧化物(BFeMn)。制备的BFeMn材料表面粗糙,疏松多孔,存在大量的Mn4+和少量的Mn3+和Fe3+(2)考察了不同环境因子对BFeMn去除四环素和苯酚的影响,结果表明,当溶液初始pH为6、温度为30℃、BFeMn投加量为0.25 g·L-1、四环素溶液初始浓度为30 mg.L-1、作用时间为96 h时,BFeMn对四环素的去除效果最优,达到99.23%;当溶液初始pH为5、温度为30℃、BFeMn投加量为0.5 g.L-1、苯酚溶液初始浓度为50 mg·L-1、作用时间为88 h时,可获得较好的苯酚去除效果(去除率 99.8%)。(3)BFeMn在去除四环素过程中,Mn4+被还原成Mn2+,Mn3+含量基本不变,而在去除苯酚过程,Mn4+和Mn3+被还原成Mn2+,Fe2+被氧化成Fe3+。FT-IR分析结果表明,BFeMn在1080 cm-1处有-OH与Mn的弯曲振动吸收峰,去除四环素和苯酚后此峰消失,很可能是因BFeMn表面羟基被四环素和苯酚的部分基团所取代,此处也可能是四环素和苯酚的氧化位点所在;790cm-1处存在Fe-O-Mn吸收峰,表明确实形成了 Fe-O-Mn复合物,去除四环素和苯酚后此峰减弱,推测可能是Mn、Fe与四环素和苯酚均发生了氧化反应。另外,BFeMn去除四环素过程中,溶液COD变化不大,pH下降,而去除苯酚过程中,COD浓度和pH均下降明显。吸附氧化实验表明,BFeMn对四环素的去除以氧化为主,对苯酚的去除以吸附为主。结合LC-MS分析结果,推测BFeMn去除四环素过程中,少部分四环素被BFeMn吸附了,大部分四环素首先脱甲基、脱羧基,转化为脱甲基四环素、脱羧基四环素,然后进一步氧化,发生开环反应,生成酮类等小分子产物,最后氧化生成甲酸、草酸、乙酸等小分子有机酸;苯酚则是大部分被BFeMn吸附了,然后部分苯酚首先被氧化为邻苯二酚、对苯二酚,继而氧化为苯醌,再进一步氧化为马来酸等中间产物,最终有部分被彻底氧化为CO2和H2O。(4)BFeMn循环再生3次后,其对四环素和苯酚仍具有较好的去除效果。溶液中共存阳离子K+、Ca2+、Mg2+对BFeMn去除四环素有一定的抑制作用,Cu2+、Zn2+对BFeMn去除四环素均存在抑制作用,且Zn2+与Cu2+存在协同抑制。Mg2+对BFeMn去除苯酚存在促进作用,Cl-、K+、NO3-、SO42-的存在会抑制BFeMn去除苯酚,苯胺与苯酚共存也会抑制BFeMn对苯酚的去除。BFeMn去除四环素和苯酚后,出水中Fe、Mn浓度均低于相应排放标准限值,生成的产物或中间产物对绿豆发芽率影响较小,说明BFeMn去除四环素和苯酚后,基本不会造成二次污染,具有实际应用的可能性。更多还原

【Abstract】 Tetracycline(TC)and phenol(Ph)are typical organic pollutants in wastewater.Although the traditional treatment method has good treatment effects on the removal of TC and Ph,it has the disadvantages of harsh reaction conditions and incomplete removal.Manganese(Mn)is a metal element with active variable valence,and its oxide is an important natural oxidant.Biological manganese oxide has better oxidation activity than natural manganese oxide.Fe3+is also oxidizing and can enhance the removal of specific pollutants.Therefore,it is an efficient water treatment technology for TC and Ph removal by materials combined by biological manganese oxides(BMn)and Fe3+,and BMn are produced by manganese oxidizing bacteria that oxidize manganese.In the present study,the composite material was prepared and applied to treat TC and Ph wastewater.The role of environmental factors on the removal of TC and Ph by the materials was investigated,and the possible mechanism of action was analyzed by combining SEM,XRD,FT-IR,XPS and liquid-mass spectrometry,as well as the possibility of the materials’ application in real wastewater,and the main findings are as follows:(1)Bio-derived ferromanganese oxides(BFeMn)were successfully prepared by using a strain of Brevundimonas diminuta(X1),a defective short-wave monospore with manganese oxidizing activity,already available in the laboratory,grouped with Mn2+ and Fe3+.The prepared BFeMn material had a rough,loose and porous surface,with the presence of a large amount of Mn4+and small amounts of Mn3+and Fe3+.(2)The effects of different environmental factors on the removal of TC and Ph by BFeMn were investigated.The results showed that the removal efficiency of TC could reach 99.23%under the condition of pH 6,temperature 30℃,dosage of BFeMn 0.25 g-L-1,TC with initial concentration of 30 mg·L-1,reaction time 96h.While Ph,in the case of pH 6,temperature 30℃,dosage of BFeMn 0.5 g·L-1,Ph with initial concentration of 50 mg·L-1,the removal efficiency was 99.8%.When the initial pH of the solution was 5,the temperature was 30℃,the dosage of BFeMn was 0.5 g·L-1,the initial concentration of Ph solution was 50 mg·L-1,and the reaction time was 88 h,the phenol removal efficiency was 99.8%.(3)The removal experiments indicated that,the application of BFeMn for TC resulted in reducing the content of Mn4+,and increasing the content of Mn2+,while the content of Mn3+was basically unchanged.For Ph,Mn4+and Mn3+are reduced to Mn2+,while Fe2+is oxidized to Fe3+.The FT-IR analysis showed that there was a bending vibration absorption peak of-OH and Mn at 1080 cm-1 for BFeMn,which disappeared after the removal of TC and Ph,probably because the hydroxyl group on the surface of BFeMn was replaced by part of TC and Ph,and the oxidation site of TC and Ph may be located here.The presence of Fe-O-Mn absorption peak at 790 cm-1 suggests that the Fe-O-Mn complex was formed,and this peak was weakened after the removal of TC and Ph,which may be attributed to the oxidation reaction of Mn and Fe with TC and Ph.In addition,during the removal of TC by BFeMn,the solution COD did not change much and the pH decreased,while during the removal of Ph,the COD concentration and pH decreased significantly.The adsorption-oxidation experiments showed that the removal of TC by BFeMn was dominated by oxidation,and the removal of Ph was dominated by adsorption.Combined with the results of LC-MS analysis,it was hypothesized that during the removal of TC by BFeMn,a small portion of TC was adsorbed by BFeMn,and most of TC was firstly demethylated and decarboxylated,converted into demethylated tetracycline and decarboxylated tetracycline,and then oxidized further to undergo a ring-opening reaction to produce ketones and other small-molecule products,and then finally oxidized to produce small-molecule organic acids,such as formic,oxalic,and acetic acid.While Ph,Most of it was adsorbed by BFeMn,and then some of it was first oxidized to catechol and hydroquinone,then oxidized to benzoquinone,then further oxidized to intermediate products such as maleic acid,and finally some of it was oxidized completely to CO2 and H2O.(4)After three times of cyclic regeneration of BFeMn,it still reached good effect on TC and Ph.The coexisting cations K+,Ca2+,and Mg2+ in the solution inhibited the removal of TC by BFeMn,and Cu2+ and Zn2+ inhibited the removal of TC and they have a synergistic inhibitory effect on TC.Mg2+facilitated the removal of Ph by BFeMn,and the presence of Cl-,K+,NO3-,and SO42-inhibited the removal of Ph by BFeMn,and the coexistence of aniline and Ph also inhibited the removal of Ph by BFeMn.After the removal of TC and Ph by BFeMn,the concentration of Fe and Mn in the effluent water is lower than the limit value of the corresponding emission standard,and the generated products or intermediates have less influence on the germination rate of mung beans,which indicates that the removal of TC and Ph by BFeMn basically does not cause secondary pollution,and it has the possibility of practical application.更多还原