硝基酚生物电化学还原性能与其结构的关系探究

发布时间：2018-10-16 17:57

【摘要】：本研究通过搭建生物电化学体系(BES),考察了不同阴极电位、pH值等参数条件下4-硝基酚(PNP)、2,4-二硝基酚(DNP)、2,4,6-三硝基酚(TNP)的还原情况,探究了其可能产生的还原产物,并对还原规律进行了对比分析。当采用不同电极材料对PNP进行还原时,采用石墨颗粒作为电极的BES无论是PNP去除效果还是PAP生成效果,均优于采用石墨毡作为电极的BES。硝基酚的还原效果受电极材料的比表面积、内阻等因素影响巨大,比表面积越大,内阻越小,则硝基酚的还原效果越好。在本研究所采用的生物电化学体系中,PNP.DNP.TNP等三种硝基酚均发生了还原。其中PNP的还原产物是PAP,且PAP相对稳定,在BES阴极未发生进一步转化；DNP的最终还原产物DAP极不稳定,无法检出,出水中仅检测到中间还原产物2-A-4-NP;TNP在该体系中首先被还原为中间还原产物2-A-4,6-DNP,其中绝大部分又被进一步还原为未知还原产物。PNP.DNP的急性毒性经还原处理后可以得到一定程度的改善,而TNP经还原后急性毒性有所上升,表明TNP的还原产物急性毒性比TNP更强。硝基酚的去除效率及去除速率随阴极电位的降低而逐渐增大,说明较低的阴极电位更有利于硝基酚的还原；硝基酚的去除效率及去除速率随pH值的升高而降低,表明硝基酚的还原情况与溶液中H+的多少密切相关,pH越低越有利于硝基酚的还原。酸性条件下,NPs去除效率大小关系依次为：PNPDNPTNP;碱性条件下,NPs去除效率大小关系依次为：DNPTNPPNP。实验表明,NPs生物电化学还原性能的强弱与其结构上氮原子的电子云密度、其在水溶液中的离子化程度以及硝基数量等多种因素有关。
[Abstract]:In this study, the reduction of 4-nitrophenol (PNP), _ 2N _ 2H _ 2N _ 2N _ 2N _ 2N _ 2N _ 2N _ 4N _ 4N _ 6 _ 3-trinitrophenol (TNP) under different cathodic potential and pH values was investigated by means of a bioelectrochemical system (BES), and the possible reduction products were investigated. The law of reduction was compared and analyzed. When different electrode materials are used to reduce PNP, BES with graphite particles as electrode is better than BES. with graphite felt as electrode, regardless of PNP removal effect or PAP formation effect. The reduction effect of nitrophenol is greatly affected by the specific surface area and internal resistance of the electrode material. The larger the specific surface area is, the smaller the internal resistance is, the better the reduction effect of nitrophenol is. In the bioelectrochemical system, three kinds of nitrophenol, such as PNP.DNP.TNP, were reduced. The reduction product of PNP is PAP, and PAP is relatively stable, and no further transformation occurs in the BES cathode, DAP, the final reduction product of DNP, is very unstable and can not be detected. Only the intermediate reduction product 2-A-4-NPNP-TNP was first reduced to the intermediate product 2-A-4-NP6-DNPs in the effluent, and most of them were further reduced to unknown reductive products. The acute toxicity of PNP.DNP could be improved to some extent after reduction. However, the acute toxicity of TNP increased after reduction, indicating that the acute toxicity of TNP was stronger than that of TNP. The removal efficiency and removal rate of nitrophenol gradually increased with the decrease of cathode potential, which indicated that the lower cathode potential was more favorable to the reduction of nitrophenol, and the removal efficiency and removal rate of nitrophenol decreased with the increase of pH value. It is shown that the reduction of nitrophenol is closely related to the amount of H in the solution, and the lower the pH is, the more favorable the reduction of nitrophenol is. Under acidic conditions, the relation of removal efficiency of NPs is as follows: under the condition of PNPDNPTNP; alkalinity, the relation of removal efficiency of NPs is DNPTNPPNP.. The experimental results show that the bioelectrochemical reduction performance of NPs is related to the electron cloud density of nitrogen atoms in the structure, the degree of ionization in aqueous solution and the amount of nitro.
【学位授予单位】：南京理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：O657.1;X703

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